







HANDBOOKS 1 



How to Run 
Engines and Boilers 



WITH A NEW SECTION ON 



Water-Tube Boilers 



PRACTICAL INSTRUCTION 
FOR YOUNG ENGINEERS 
AND STEAM USERS :: :: :: :: 

BY 

EGBERT POMEROY WATSON 

Author of: Modern Practice of 
American Machinists and Engineers- 
Manual OF THE Hand Lathe— The Pro- 



FOURTH EDITION 



NEW YORK : LONDON : 

Spon & Chamberlain, E. &. F. N. Spon, ltd, 

12 cortlandt street 125 strand 

1899 



TWO COPIES RECEIVED, 

L (bra ry of Congre«3| 
Office f the 

R«gUt*r of CopyrlghtSi 



I 7^^-i' 



48665 



ENTERED ACCORDING TO ACT 

OF CONGRESS IN THE YEAR l8o2, V.V 

E. P. WATSON & SON « 1899 ^^' SPON & CHAMBERLAIN 

IN THE OFFICE OF THE LIBRARIAN OF 

CONGRESS, WASHINGTON, D.C 



b- ) ^ 




SECOND COPY, 



THE BURR PRINTING HOUSE, NEW YORK. 






PREFACE TO FOURTH EDITION. 

The author has carefully gone through this 
little work, and at the suggestion of the pub- 
lishers has added twenty-eight pages of new 
matter treating upon the subject of Water- 
Tube Boilers, their management, maintenance, 
and efficiency for marine and land service. 
Eight cuts, illustrating the principal types of 
Water-Tube Boilers, have also been included. 
While the space given to the treatment of this 
subject is necessarily limited, still the pub- 
lishers believe it will add additional value to 
the work and prove of considerable interest 
and use to the engineer. 

The Publishers. 

New York, October 8, 1899. 



CONTENTS. 

CHAPTER I. PAGE 

The First Thing to be Done i 

Cleaning the Boiler 3 

Removing Scale 5 

Caution in Handling Caustic Potash 6 

CHAPTER n. 

Using Scale Preventers 7 

Oil in Boilers 9 

Braces and Stays 9 

CHAPTER HI. 

Mud Drums and Feed Pipe 11 

Boiler Fittings 12 

CHAPTER IV. 

Grate Bars and Tubes 15 

Bridge Walls 17 

The Slide Valve Throttling Engine 18 

CHAPTER V. 

The Piston 22 

The Slide Valve 24 

CHAPTER VI. 

Testing the Valve with Relation to the Ports . . 2^ 

Defects of the Slide Valve 30 



Vlll CONTENTS. 

CHAPTER VII. PAGE 

Lap and Lead ^3 

The Pressure on a Slide Valve 34 

Stem Connections to the Valve 36 

CHAPTER VIII. 

Valves off their Seats 40 

Valve Stem Guides 41 

Governors 42 

Running with the Sun 44 

CHAPTER IX. 

Eccentrics and Connections 46 

The Crank Pin 48 

Brass Boxes 51 

Bearing on Pins 53 

Fitting Brasses to Bearings 55 

CHAPTER X. 

Adjustment of Bearings 57 

The Valve and Gearing 58 

CHAPTER XL 

Setting Eccentrics 65 

The Actual Operation 67 

CHAPTER XII. 

Return Crank Motion 74 

Pounding 75 

The Connections 77 

Lining Up Engines 82 



CONTENTS. ix 

CHAPTER XIII. PAGE 
Making Joints 88 

CHAPTER XIV. 
Condensing Engines 93 

CHAPTER XV. 

Torricelli's Vacuum 100 

Proof of Atmospheric Pressure loi 

No Power in a Vacuum loi 

Pumps 105 

CHAPTER XVI. 
Supporting a Water Column by the Atmosphere 107 

CHAPTER XVII. 
Starting a New Plant 114 

CHAPTER XVIII. 

Water-tube Boilers . 122 

Boiler Explosions 122 

Economy of Maintenance 123 

Evaporative Efficiency 124 

Why Water-tube Boilers Steam Rapidly .... 140 

Torpedo-boat Boilers 141 

Management of Water-tube Boilers 146 

CHAPTER XIX. 

The Highest Qualities Demanded 150 

The Man Himself the Factor 151 

Lastly 152 

Index 155 



INTRODUCTION. 

Prefaces have gone out of fashion. They 
are usually excuses, or explanations, or apolo- 
gies, or something akin, for having written 
what follows them. This little book needs no 
preface, but here is one and a dedication as 
well, for in this work I have endeavored to 
serve young American Engineers who have 
taken to the business seriously by mentioning 
a few troubles they are likely to encounter ; but 
it is only mention, for the one thing which can 
not be imparted is experience. Time, study, 
and practice alone can give it. No man was 
ever made an engineer by a book or by rules, 
but every engineer must know the first prin- 



IV INTRODUCTION. 

ciples and traditions of his business. The in- 
experienced will find a few of them herein. 
This little book is dedicated to American 

Engineers, the men who have always helped 
me on my way and who have always kept faith 
with me; who have always held out the right 
hand of fellowship to me as man and boy, by 
their sincere friend and well wisher. 

Egbert Pomeroy Watson. 



HOW TO RM EEIMS AND BOILERS. 



CHAPTER I. 

The first thing to be done upon taking 
charge of an engine and boiler, new or old, 
is to examine the boiler thoroughly. No 
matter whether it has just come from the 
shop, or has been run for years, take off the 
man-hole plate and go inside yourself with 
a hand-lamp ; after you are in look at all the 
water spaces, and see if they are clean, that 
is, without rubbish or dirt of any kind. Even 
new boilers are not free from this. There 
are various irresponsible persons about 
boiler shops who are not as careful as they 
should be, and it will be the exception rather 
than otherwise if you do not find a lot of 
things which are better out of the boiler than 
in it. In large boilers rivet kegs are often 
taken in to sit upon, and are not always taken 
out again ; the staves are thrown down in the 
water space, from whence they will float out 
and get in the steam pipes by some mysterious 
happening. The water line is not so high as 
the steam pipe, by any means, but the staves 
get there somehow ; so do bunches of waste, 
etc. Everything of any kind should be 
cleaned out of the boiler before w^ater is run 



into it. To do this it will be necessary to take 
off the lower hand-hole plates, and with a 
small hooked rod dislodge everything that is 
loose in the boiler. 

Spare no pains in this work, for it will be 
labor and money saved in future. When 
the boiler is thoroughly clean you can put the 
plates in again, but before doing this rub the 
gaskets thoroughly with plumbago, and they 
will not adhere to the plate where exposed to 
heat. This is a saving of time and gaskets in 
breaking joints in future. The old way of 
making joints upon hand-hole plates, with 
hemp gaskets slushed with white lead, has 
gone out of use, having been superseded by 
rubber gaskets made for the purpose. If you 
are remote from a city, however, and cannot 
get a rubber gasket, you can make a hemp 
gasket which will answer all purposes. Jute 
IS the best material for this job if it can be had, 
but you are quite as likely to be out of jute as 
out of rubber gaskets, and if you have neither 
you can get a clothesline most anywhere. 
Unlay this and take the twist out of it; beat it 
with a fiat stick so as to reduce it to its original 
fiber ; then braid it up again of the proper size 
for the job in hand. Find the right length for 
the gasket, and join the ends so as to form a 
ring of the proper size that will fit the plate ac- 



3 

curately : it should go on so tight that you 
have to force it over the flange of the plate. 
Cover this gasket thoroughly with white lead, 
and then put it in its place. It will be abso- 
lutely tight if the v/orkhas been properly done. 
Cleaning the Boiler. 
We have been assuming that the boiler you 
have taken charge of is a new one, without 
scale, but it it is an old one there is likely to be 
a quantity of scale and dirt, which must be 
taken out at once. The way to do this is to 
us the best tools you can get hold of, or con- 
trive for the purpose. The place to look for 
dirt and deposits from the feed water is in the 
bottom of the boiler furthest from the entrance 
of the feed water, and in the parts that are the 
coolest, if there are any, when the steam is on. 
In a return tubular boiler this is generally in 
the smoke-box end, which is not so hot as the 
fire-box end; the quantity of rubbish which ac- 
cumulates in a neglected boiler is astonishing, 
and you must not be surprised if you have to 
remove wheelbarrow loads. This dirt comes 
from the solid matter in the water, both that 
which is carried in mechanically from turbid 
supplies, and that which is held in suspension 
until set free by heat. Every gallon has a cer- 
tain amount, and as many gallons are evapor- 
ated daily, unless removed weekly it soon 



makes a wheelbarrow load. This dirt, by 
backing up against the flue sheet, deprives the 
ends of the tubes of water, which not only 
steals part of the heating surface, but destroys 
the ends of the tubes and flue-sheet by corro- 
sion and over heating, so that it is only a ques- 
tion of time when the boiler will be practically 
useless. If the lower course of the tube-ends 
in the smokebox leak, be sure that they have 
been abused in the manner stated. You will 
probably find that they will leak after dirt has 
been cleaned out. In that case the tubes must 
be re-expanded, and to do this a boiler maker 
must be called in. Do not, upon any con- 
sideration, try to tinker them up with a ham- 
mer yourself. You will only make a bad mat- 
ter worse, and set other tubes to leaking which 
were tight. Having taken out what may be 
called the "loose dirt," though some of it is 
very far from being loose, you will find 
another job in front of you, and that is to get 
out the dirt which is fast. In other words, the 
scale. This is actual stone, artificially formed 
within the boiler from the working of it. It 
differs in character with the kind of water 
used. If it is hard water, so-called, it will be 
limestone scale ; if soft water, it will be sul- 
phate of magnesia and soda scale ; either one 
of them is bad enough, so far as the boiler is 



5 
concerned, and must be removed absolutely if 
there is to be any economy. 

Removing Scale. 
There is a way to do this which we have 
practiced with success, and that is to run the 
boiler full of water up to the third gauge and 
then put in a quantity of a scale preventive. 
Of these there are numbers in market, but we 
do not name any one as the best. Doubtless 
none of them are wholly useless, though some 
of them are inert or do not act. You will have 
to find out by experience which one serves 
your purpose. Sometimes caustic potash 
answers a very good purpose. This when the 
scale is chiefly mud with sulphate of soda and 
magnesia combined. Caustic potash is the 
concentrated lye sold in grocery stores, but if 
wanted in large quantities should be purchased 
of wholesale druggists. To use it, dissolve it 
in a barrel of water, say 40 pounds to the bar- 
rel, and pour it into the boiler. This is about 
one-sixth of a pound of potash to the pound of 
water, and is strong enough for the purpose. 
After the purger is in the boiler build a light 
fire and heat the water to boiling point, and 
then haul the fire and let the contents stand. 
It is better to do this on Saturday night, if pos- 
sible, leaving the water in the boiler until Mon- 
day morning ; you should then get up steam 



to, say, five or ten pounds pressure on the 
same water, haul the fire all out, and blow the 
boiler down. You will, in the majority of 
cases, find the boiler thoroughly clean, except 
for chunks of scale which cannot go through 
the blow-cock, and which must be taken out 
through the hand-holes. 

Cautiojst. 
In handling caustic potash the utmost care 
must be used. It is truly caustic, or burning, 
and if a portion gets in the eyes it will cause 
serious trouble. The same is true of sores on 
the hands. Handle it with gloves; treat it 
very respectfully. 






%' 



t 



CHAPTER II. 
Using Scale Preventers. 

If caustic potash cannot be had, a substitute 
may be found, in rural districts, in slippery- 
elm bark. This is not at all caustic, but quite 
the reverse, being demulcent in character. 
How it acts we do not know ; but that it has a 
certain efficiency we do know, because we 
have cleaned boilers thoroughly with it. It 
makes little difference how much is used, put 
it in the boiler and let it stay there for a week, 
and there will be a benefit from its use. 

These purgers just named are only of service 
where the scale is soft ; for hard scale a differ- 
ent one must be used, and to attack lime scale 
it should be of an acid character, for lime is 
alkaline, and its antidote is an acid. But just 
here trouble is likely to ensue in the hands of 
an inexperienced person. A good many will 
exclaim loudly against using an acid purger in 
a boiler, arguing that it will destroy the boiler 
as well, and that very soon. Some have shown 
us pieces of iron, that they immersed in certain 
boiler purgers, that were badly corroded. This 
is very likely, but it so happens that no boiler 
purger is used in that way. The purger is 
largely diluted wuth water, and acts very slowly 
upon the iron. It attacks the scale first, be- 



8 

cause it has the greatest affinity, or liking, for 
it; after that it goes for the boiler plates; but 
there are no after effects ot this character from 
a boiler purger, because it is no longer in the 
boiler when the scale is removed, and if a 
boiler is thoroughly washed out there is no 
danger to it from the use of a strong purge. 
There is very great danger from the presence 
of heavy lime stone scale, and since nothing 
but a purger with an acid reaction will remove 
it, w^e do not fear to use it ourselves. Some 
engineers have shown us boilers from which 
the scale was removed w^hich had the plates 
badly corroded. This action was attributed to 
the use of the purge, when it was, in fact, 
caused by the scale itself. The corrosion was 
going on all the time underneath the scale, and 
when it was removed the injury it caused was 
manifest. Ot two evils we are taught to choose 
the least, and in this case the use of a strong 
boiler purger is less than the injury and loss of 
fuel caused by scale. Get that out first, 
thoroughly clean the boiler after of all traces 
of the purge, and there will be no trouble aris- 
ing from its use. It is understood, of course, 
that after the use of any boiler purge that the 
hand-hole plates must be taken off and the 
boiler cleaned out by hand, washed with a 
hose, and then filled up and blown out again 



9 

before steam is raised. There is no middle 
g-round or half-way measures possible in deal- 
ing with a dirty steam boiler. Get down to 
the naked iron and keep it so, inside and out, 
and the boiler twenty years old will steam as 
freely as one just out of the shop. 
Oil in Boilers. 

Do not upon any account put crude oil or 
any other kind of grease in a steam boiler. It 
g-enerally gets in fast enough through the 
feed water where open heaters are used, 
without putting it in. The effect of putting 
oil in is, in a great many cases, to cause the 
crown sheet to come down, or the lower 
sheets to bag. When first put in the oil floats, 
but it gradually picks up scum from the sur- 
face, in which scum there is always more or 
less actual mud thrown up from the bottom by 
the boiling water; the oil then becomes like tar, 
and being heavy settles on the plates and 
sticks fast. Since the water cannot get under- 
neath it the plates are overheated and come 
down, notwithstanding the fact that there is 
plenty of water in the boiler. Keep every kind 
of grease out of a steam boiler, if you have 
to filter the feed water to do it. 
Braces and Stays. 

We have now a clean boiler to deal with ; 
let us see in what condition it is as regards 



lO 

strength. The braces are the first to be con- 
sidered. Perhaps some of them are carried 
away entirely; such a state of things is by no 
means unknown. They must be replaced at 
once by boiler makers, who should also go 
over every other part of the boiler and test it 
for condition; but if there are no boiler makers 
handy the engineer must do it himself. The 
boiler most generally used is the return 
tubular, which is a plain cylinder with an ex- 
ternal fire-box, from which the heat traverses 
the bottom and enters the tubes at the back, 
passing through them to the breeching and 
smoke-stack in front. The weak point in the 
return tubular boiler is directly over the bridge- 
wall, where the heat deflected from the wall 
strikes upon the shell. This spot needs to be 
carefully examined, for unless the boiler has 
been well taken care of it wll be found weak 
and unsafe. If any doubt exists, a half inch 
hole should be drilled in the bottom to ascer- 
tain the exact thickness of the plate, when, if 
thinner than the shell elsewhere, it should be 
removesd, and a new plate put in. The sides 
of the boiler should also be examined near the 
wall, or where the boiler meets the brick^work, 
for here there is often trouble from corrosion ; 
also at the junction of the blow-pipe in the 
bottom or at the end of the boiler. 



CHAPTER III. 
Mud Drums and Feed-Pipe. 

If there is a mud-drum attached to the boil- 
er examine it very thoroughly, for explosions 
of mud-drums are very common. If the mud- 
drum is buried, as it often is, it is probably 
corroded greatly. The proper place for a 
mud-drum is outside of the boiler, in plain 
sight, where it can be got at and cleaned out 
weekly. The object of it is to catch all the free 
mud, so to call it, which is thrown down at 
night when the boiler is not running. With 
some water used for steam making, as on 
Western rivers, the quantity of mud so de- 
posited is very large, and if not removed it 
will be driven back into the boiler. This is 
particularly true where the feed pipe enters 
through one end of the mud-drum. It does 
not require much thought to see that this 
wholly defeats the object of the mud-drum, for 
the sediment which collects over night is 
forced through the boiler again at the first 
stroke of the pump in the morning. 

As to the best place for the feed pipe to enter 
the boiler there is a difference of opinion 
among engineers, but there is no doubt but that 
the worst place is through the mud-drum, for the 
reason given. Some think that the feed should 



12 

enter the coolest part; some put it in the steam 
space, and some enter it at the front end 
alongside the fire. An objection to this is the 
bad effect of water cooler than the water in 
the boiler upon hot plates; an advantage is 
the propulsion of any sediment that may lie 
upon the bottom of the boiler to the back end 
of it, where there is no trouble in removing it; 
another benefit is that the mechanical action 
of the entering jet assists the circulation by 
forcibly driving the heated water from the 
front to the back, and replacing it with cooler 
water, but to effect these objects the feed pipe 
must project within the boiler for a few inches 
so as to give what we shall call a straight 
shot from it. 

Boiler Fittings. 
In these are included every sort of attach- 
ment to a boiler, the water gauge, gauge cocks, 
safety valve, checks of all kinds, and the blow- 
off valve or cock for blowing the water out of 
the boiler. This last is a much more important 
detail than it is generally supposed to be, and 
many accidents nave happened from careless- 
ness with it. These accidents occurred from 
** sticking" any sort of a bent pipe (we have 
actually seen an old leader pipe from a house 
used) over the end of the nipple or elbow on 
the blow-pipe. The blow-pipe connection 



13 

should be made as firmly and as securely as 
any other attachment to a boiler. If one re- 
flects for a moment, it is easy to see that there 
is a tremendous strain on a pipe which is dis- 
charging a two inch stream of water under 60 
or 70 pounds pressure. A boiler never should 
be blown off at this pressure, but it sometimes 
has to be, and preparation should be made for 
it. No elbows should be used where it is pos- 
sible to avoid them ; the pipe should run as 
straight as it can from the boiler to the outer 
air, and if a cock is used care should be taken 
that it is always in perfect order. It should not 
leak a drop ; the bolt at bottom which keeps 
the plug in the cock should be accurately fitted, 
of full length, entering the plug not less than 
i^ inches, and have a good head on it. It 
must never be meddled with or touched, except 
to open or close it, when under pressure. 
Don't hit it with a hammer, either on the under 
side to start the plug up if it sticks, or on the 
top for any purpose. Remember that it is 
under pressure, and if it gives way it is almost 
certain death to any one near it. Defer all tin- 
kering and investigation until the boiler is cold; 
or, in other words, make everything secure be- 
fore steam is on; then there will be no trouble. 
Forethought, care, and caution, are absolutely 
indispensable qualifications in an engineer, and 



14 

it is useless to expect success or ordinary 
economy without them. No man can be an 
engineer worthy of the name who is careless 
or has not his wits about him at all times. 
Mr. I-Didn't-Think has no business with a 
steam boiler. 

What has been said of the blow-cock is true 
of all the other fittings. Every one of them 
must be in perfect order to be safe and efficient; 
an engineer must bear in mind that he is deal- 
ing with a tremendous agent, which is safe 
only when in its place and under control, and 
every gauge or fitting of every kind must be 
securely in place and tight of itself, that is, 
tight without makeshifts of any kind. 

The safety valve in particular must be tight, 
for a great deal of coal can be lost by a leaky 
valve. It should be free and clear in the hoist, 
or where the lever is to be raised — if it is of the 
lever type — and entirely free from rust in all 
parts. A safety valve is for use, not for emer- 
gency, and if it is not in order it will not act 
when the emergency comes, if it ever does. 

It is not every engineer that can do the work 
which we have mentioned with his own hands, 
for not all persons in charge of engines are 
machinists; these instructions convey a knowl- 
edge of what is needed, and the work can be 
supplied by those competent to perform it. 



CHAPTER IV. 
Grate Bars and Tubes. 

One of the most important parts of a boiler 
is the ^rate. Curiously enough but few give 
this matter sufficient thought, but it is plain 
upon reflection that the air which is needed to 
support combustion must be supplied through 
it. If the bars are warped and broken, too 
much air goes through them, with the effect of 
wasting fuel or checking the free steaming of 
the boiler. Moreover, a broken grate bar pre- 
vents proper firing, or attention to the fire ; all 
the bars should be, in good order, with no open 
spaces at the ends (front or back) or sides. As 
this bears directly upon the subject of combus- 
tion, it will be more explicitly alluded to fur- 
ther along in this work. 

The tubes or flues particularly demand at- 
tention, and must be absolutely clean inside 
and out. In a former article we have given 
directions how to clean them outside — that is, 
on the water side, but they must be clean on 
the fire side too. With anthracite coal this is 
not a matter of difficulty, but with soft coal it 
is ; not so much through the soot which accu- 
mulates in them as with the ** gurry,'' for want 
of a better name, which is burned on. This 
last IS the tarry distillates of the coal, or heavier 



i6 

products of combustion, which are condensed 
on the inside of the tubes when the boiler is 
comparatively cold, or in getting up steam 
every morning, and is by no means easy to 
remove. It not only checks steam making by 
obstructing the heat from passing through the 
tubes, but it hinders the draught by the ad- 
herence of soot and roughening the surface of 
the tubes. It would seem that the fire should 
burn this deposit off, but it requires a much 
higher temperature to do this than that in the 
tubes, and the only way to remove it when it 
has accumulated in quantity is to thoroughly 
slush the tubes with crude petroleum oil, ap- 
plied with a swab and allowed to remain for a 
day or so, when it should be sw^abbed out 
again. This is a job which but few persons 
care to undertake, particularly if the boiler is 
large, but in some cases it becomes neccessary. 
Crude petroleum is a solvent for tar, and will 
clean the tubes thoroughly. 

Of course it has to be undertaken in holiday 
time, when the boiler is idle for a day or two, 
for to be of any service the oil must remain in 
the tubes at least 24 hours. It is of no use to 
try to rasp this *' gurry" out with steel brushes 
or scrapers. It is as tough as India-rubber and 
a scraper slides over it. 



17 

Bridge Walls. 

The bridge wall in a boiler is intended to 
delay the products of combustion in the fire- 
box as long as possible, and to confine the 
heat from the fire within the area of the grate. 
To do this it is manifest that the throat, or 
opening over the bridge wall, between the top 
of it and the boiler, should be as small as it 
can be, and leave room enough for a good 
*' draught," so-called. There is, however, a 
danger in this, and this danger is that if the 
throat is too narrow, the heat, and sometimes 
the flame, is sharply deflected and concentrated 
directly upon one spot over the v/all. The 
result of this is that the sheet for a foot or so is 
fire-eaten, or thinned and weakened ; it is 
burned, as boiler makers would say, notwith- 
standing there may have been plenty of water 
in the boiler. The opening over the bridge 
wall should never exceed ten inches, nor be 
less than eight inches, and it should follow 
the curve of the boiler. There are a great 
many patents on bridge walls which are in- 
tended to improve the combustion by admit- 
ting air over them, or through them, but never 
having had any experience with them we can- 
not say anything about them. 

Assuming that the boiler has been put in 
good condition, we will look at the engine. 



i8 

The hints given in the previous chapters 
should enable any intelligent man who is fit 
to be about a steam plant, to have a boiler 
v^hich will steam freely and as economically 
as its construction will allow. A treatise 
could be written upon boilers alone, and many 
such works are in existence. The contents, 
however, relate more particularly to the con* 
struction, a matter which does not enter into 
an engineers duties. 

The Sode- Valve Throttling Engine. 
The commonest form of steam engine in use 
to-day is the slide-valve throttling engine, 
which is regulated by governors of various 
kinds. It is the simplest of machines, easily 
managed by any one after a little instruction, 
and frequently is found in charge of men and 
boys who have had no experience whatever, 
they merely knowing that a certain valve has 
to be opened, and that the engine must be at 
half-stroke to start. Such persons are not en- 
gineers in any sense of the word, for they do 
not intend to follow the business any longer 
than they can help. Our instructions are not 
directed to them, but to intelligent young men 
who have started with the intention of learning 
all that they can. The first thing to do then in 
taking charge of an engine is to see in what 
condition it has been handed over, in order that 



19 

you may not be blamed for the sins of those 
who preceded you. The cylinder is the seat of 
power, and we want to examine it as soon as 
we can get a chance. If we have been under 
steam the day before, we leave the eng^ine on 
the back center at night (Saturday night foi 
instance), and take off the cylinder head. The 
piston is then at the end of its stroke, and we 
have an opportunity to see what the clearance 
is between the piston and the cylinder head. 
The latter detail will leave its mark on the 
cylinder after it is taken out, so it will be easy 
to measure directly from the piston to the said 
mark. Some clearance is necssary for safe 
working, but it should be just as little as pos- 
sible ; clearance is waste room that has to be 
filled with live steam at every stroke before 
any work is done on the piston. 

As a rule excessive clearance is given in 
small engines, for no reason whatever, except 
that some builders appear to think that there is 
less danger of breaking down. Suppose that 
the cylinder is 12 inches diameter: then the 
piston should run within one-quarter of an 
inch of the head. If the piston is of that class 
where the follower bolts stick out the depths of 
their heads, it canuot run so close as this, and 
probably there is an inch or more clearance 
in such a cylinder, but it is easy to reduce the 



20 



clearance in such cases to the lowest point, 
pnd this is easily done by taking* the follower 
to a machine shop and having the bolt holes 
counterbored, so as to let the heads in as far as 
possible; having done this, fill up on the head 
itself by bolting on a cast-iron plate of the re- 
quired thickness, cutting out where it covers 
the steam port. The reduction of clearance 
often makes a boiler much larger; or, in plainer 
terms, since less waste occurs it is easier to 
keep steam on a boiler than when the clear- 
ance is excessive. Having found what the 
clearance is on the back end then, we discon- 
nect the piston from the cross-head, and (run- 
'ning the crank on the forward center), we 
find what it is on the front end. This we do 
by shoving the piston clear up against the for- 
ward head. Having done this w^e measure 
from the follower back to the end of the stroke, 
as shown by the wear on the guides, and the 
wear on the cylinder itself. If this measure- 
ment is half an inch longer than the working 
stroke of the piston, there is half an inch 
clearance on the front end, and as there are no 
follower bolts on that end it is all waste, ex- 
cept so much as is actually needed for the safe 
wording of the engine. We should, if the en- 
gine was ours, reduce this clearance also, to 
the same degree that we did the back end, but 



21 

as it entails more or less work for the shop, it 
will be as well to leave the clearance half an 
inch on the front end; if the clearance is one 
inch, however, no consideration of trouble or 
expense should be spared to reduce it in the 
same way that we fixed the back head, by- 
adding to the head itself. The clearance in 
any engine must be reduced to its lowest 
terms, for by doing this, if the engine is yours, 
you put money in your pocket; if it b elongs to 
some one else and you are in charge of it, you 
get the credit of making a saving, and this will 
be a feather in your cap worth working for. 



^fe 




-m^ 



CHAPTER V. 
The Piston. 
Now that we have the clearance matter at- 
tended to, let us see what kind of a looking- 
thing we have for a piston. This detail of a 
steam engine is of all conceivable forms— and 
some inconceivable forms, to any one who 
thinks what a piston has to do. They are 
made as heavy as hydraulic plungers, and with 
as many attachments as possible, in the shape 
of rings, with springs to keep the rings out to 
the cylinder, and screws in the springs to keep 
the springs out to the rings. The reason that 
some firms make them in this way is because 
their grandfathers made them so, and that is 
reason enough in their eyes. If the piston 
you have taken out is of this class it is your 
and the owner's misfortune, but as we are not 
giving instructions upon how to build engines, 
we will merely state how this old-fashioned 
piston is to be put in as good condition as pos- 
sible. Pistons are liable to become leaky in 
the following places : between their flanges 
where the rings bear; between the rings and 
the cylinder itself; through the follower into 
the body of the piston. Wherever there is a 
joint look for a leak, for joints become imper- 
fect through use and time. If the rings move 



23 

back and forth between the flang^es of the 
piston they leak, and must be made tight by 
skinning off the follower. This is of course a 
shop job, wath which the engineer has nothing 
to do, but before the piston is sent to the shop 
for repairs the engineer should be sure that the 
piston needs it. Very often it will be found 
by examination that dirt or '^ burrs " have got 
in betw^een the follower and the spider, or else 
the thread on the bolt-holes in the spider has 
been raised around the edges, so that the fol- 
low^er will not go dowm, iron and iron. An 
experienced engineer will soon find out 
whether these things have happened by taking 
a smooth file and going carefully over the fol- 
low^er-seat on the spider, or main casting of 
the piston. In this way he will find all the 
burrs or bruises that have raised the surface, 
and dress them off level ; then w^hen he puts 
the follower on again and screws it up solid 
without the rmgs in, he should take a hammer 
and strike on the outside of the follower 
opposite solid iron. If the follower is tight on 
its seat it will sound like striking on an anvil ; 
if it is leaky the sound given out will be like 
striking a piece of iron lying on an anvil. 
Leaks can also be told by the appearance of 
the parts, but as this is not easily conveyed in 
print we shall not attempt it. The best way 



24 

in all cases is to send the piston to a ^ood 
machine shop and have it put in perfect order, 
and this is why it was taken out the first thin^, 
so that it mig;ht be going forward while we are 
dismantling other parts of the engine. 
The Slide Valve. 
The next thing we do to ascertain the condi- 
tion of our engine is to take the bonnet off the 
steam chest and see in what shape the valve 
and its seat are. An inexperienced man is very 
likely to get into trouble here, and do damage 
to the engine. Bolts and nuts which have been 
long undisturbed are very hard to start, and in 
very many cases they either break short off in 
the casting, or else, in the case of stud bolts, 
come away at the bottom, and unscrew from 
the casting. Either of these misfortunes is 
bad, because it is not an easy task to get out a 
broken stud bolt, or to make one tight in its 
seat after it has been forcibly removed ; there- 
fore, if the nuts do not yield to moderate force 
exerted on a wrench, pour a little kerosene on 
them and let them stand half an hour. Kero- 
sene is the most pervasive fluid known to the 
trade, and it will seep into the most minute 
crevices; if after its application the nuts will 
not then start, get an iron ring, or a big nut 
with some body of metal in it and heat it red 
hot. Put this over the stubborn nut until it has 



25 

become very warm and it will come away 
without any trouble. 

If we digress here for a moment it is because 
the occasion seems to demand it. This digres- 
sion is to again insist upon the necessity of 
care and caution in dealing with a steam en- 
gine. It is no evidence of skill for a man to 
go at a steam engine with a hammer and 
wrench and slaughter right and left, for by pur- 
suing this course he can do more damage in a 
moment than he can repair in a day, and he 
can save both time and money by going at 
every job in a workmanlike manner. 

The slide valve is really the heart of the 
steam engine, for upon its perfect condition 
and perfect action everything depends ; if it is 
off its seat or badly set there can be no econ- 
omy. When we take up a slide valve in an 
old engine we shall, in nine cases out of ten, 
find it in very bad condition. This is owing, 
in a great measure, to the way in which it is 
connected to the mechanism that operates it, 
and to the way in which it is constructed. 
Most slide valves are extremely faulty in this 
respect. In order to keep the steam chest as 
short as possible, the valve seat is made short, 
and very often the valve overruns the seat, so 
as not to wear a shoulder on it. The valve 
stem, acting on the stuffing-box as a fulcrum, 



26 

tends to pry the valve off its seat, notwith- 
standing the pressure upon it, with the result 
that the face of the valve is worn rounding in 
the direction of its stroke. Where this is the 
case it must necessarily leak, for a slide valve 
seat is like the slide valve itself — if one is 
rounding the other must be hollow, in some de- 
gree, unless it is very much harder than the 
valve itself. The time to test a valve for leaks 
is when the engine is running, and it can be 
told very quickly by watching the exhaust 
where it can be seen. If this is sharp and 
clear at every stroke the valve is tight, but if it 
is followed by a secondary jet that scarcely 
clears the exhaust pipe, the valve or the pis- 
ton leaks, and quite likely both ; any leak 
through the piston would also show on the ex- 
haust, but in this case, unless the piston leaks 
very badly indeed, it is likely to be a leak of 
the valve which shows on the exhaust. To 
test it for condition, obtain a straight edge and 
laj'" it across. Hold the straight edge absolute- 
ly vertical, not tipped to one side, and it will 
soon show in what condition the valve and the 
seat are. The remedy for a leaky slide valve 
is in the machine shop. 



CHAPTER VI. 

Testing the Valve with Relation to the Ports. 

To find out whether the valve is properly 
made in the first instance, or whether it has 
been tampered with by some engineer in 
charge before you, proceed as follows : — Take 
a sheet of paper large enough to entirely cover 
the valve seat and lay it on it. Rub all over 
the edges of the ports so as to obtain a fac 




Fig. 1. 
simile of them. Then get a piece of pine half 
an inch thick and three inches wide, and put 
the edge of it on the diagram, transferring the 
ports to the stick, thus: — Do the same to the 
valve, and you will have a fac simile of the 
valve and its ports, which can be more readily 
handled than by taking the valve itself, which 
is heavy and hard to see distinctly when in 
the chest. Now these directions sound very 
simple, and are very easy to understand by 



28 

one who knows all about the matter before- 
hand, and who knows what he expects to see, 
but they are not so simple to a young man 
who reads them for the first time, or who is 
unacquainted with the action of a slide valve, 
and it is mainly to readers of this class that 
this work is addressed. But we will try to 
make it as simple as possible, and so that any- 
one without previous knowledge of a slide 
valve can see at a glance whether it is properly 




Fig. 2. 

made or not. Actual comparison of the valve 
and valve seat templets will appear further on. 
Let us say, however, that there are slide 
valves of many kinds, flat faced, round faced 
(as in the case of a piston slide-valve), V faced, 
etc.: but in this article, when we say slide 
valve we refer especially to the common cast- 
iron box without a bottom, which is generally 
used in engines, as shown in the engraving, 
fig. 2. This covers both ports and extends 
some distance over them on each side. That 



29 

IS to say, the end of the valve laps over the 
ports, and the part projecting* is 'jailed the lap 
of the valve. The cavity inside the valve is 
the exhaust port of the valve, and this also laps 
over the exhaust edge of the steam port some- 
times; the outside lap is called steam lap, or 
lap on the steam side, and the inside lap is 
called exhaust lap — when there is any. Usually 
the exhaust port in the valve coincides with 
the inside edges of the steam ports as shown in 



steam lap 




Fig. 3. 

fig. 3, and when in this condition it is said to 
have line and line exhaust. Sometimes the 
exhaust is given clearance ; that is to say, the 
steam port on the exhaust side is open slightly, 
and when in this condition it is said to have 
exhaust lead, or lead on the exhaust side. A 
slide valve then, works normally, that is to 
say naturally, under these conditions : It is a 
cast-iron box covering both ports all round, so 
that no steam can get into the cylinder unless 



30 

the valve is moved so as to expose one of the 

ports. To recapitulate : the part which projects 

over the ports is called steam lap; the inside 

cavity of the valve is the exhaust port ; the 

inside edge of the steam port is the exhaust 

side ; the outside end of the valve is the steam 

side; and the same on both sides of course. 

These details are, naturally, familiar enough to 

experienced engineers, but we must not forget 

that there are young men coming into the trade 

continually w^ho have all their trade before 

them, and who have it to learn as we had to, 

and it is for them that these explanations are 

given. Let us now look at the action of the 

valve. 

Defects of the Slide Valve. 

Were it not for one inherent, and we may say, 
hereditary defec^, the slide valve would be the 
ideal one for its purpose, for all the functions 
are performed by one valve. This defect is 
that it is limited in its application to working 
steam expansively. As will be readily seen 
by anyone who uses the templet, fig. i, where 
the valve face is shown in section, when it is 
applied to the valve and moved to the various 
positions of opening and closing the valve, the 
exhaust is more or less throttled or choked ; its 
area is greatly reduced, so that escape of the 
exhaust is delayed. The resnl.t of this is that 



31 

the exhaust steam presses back on the piston 
(back pressure so-called), and takes away just 
so much from the power of the live steam on 
the other side which is driving the piston for- 
ward. This back pressure varies in amount 
with the position of the valve and the point of 
the piston stroke at which the valve closes. 
For instance, in plain words, when a slide 
valve cuts off at three-quarters of the piston 
stroke there should be little or no back pressure 
in a properly constructed valve, for the exhaust 
is open long enough to allow all the dead steam 
to escape, but at points of the piston stroke 
under three-quarters the exhaust is not free, 
and a cut-off obtained with a common slide 
valve under five-eighths of the piston stroke has 
to be paid for by loss of live steam pressure. 
Notwithstanding this fact there are many slide 
valves cutting off to-day at one-half of the 
stroke, and under that at times, and the de- 
signers of them are satisfied — that is to say, 
they have to be satisfied — for the common slide 
valve will always create undue back pressure 
at points under'^Ieven- sixteenths of the piston 
stroke. This is shown very plainly by indi- 
cator cards, where the last part of the exhaust 
is caught in the cylinder by the piston and 
pushed uphill, if we may so express it, until 
(when nearly on the center) there is a pressure 



32 

opposed to the piston closely approximating 
boiler pressure. Whether this is economy or 
not every one must judge for themselves. To 
expend live steam pressure and power stored 
in the flywheel in trying to make dead steam 
alive, by squeezing it between the piston and 
cylinder head, always seemed to us unwise, 
for the reason that we do not get back as much 
work from the imprisoned steam as we spent 
to catch it, but as it is no part of our intention 
to discuss moot points or theories in this series, 
we go no further in this direction. 



•\<C5^ rx®T^_^ ''<^J>' 



:^^t3 






CHAPTER VII. 
Lap and Lead. 

The object of putting- lap on a slide valve is to 
cut off the steam early in the stroke of the 
piston. Suppose the steam end of the valve 
had no lap at all, but barely covered the steam 
port: then so soon as the piston moved the 
valve would open and continue opening-, clos- 
ing barely in time to open again for the return 
stroke of the piston. Now suppose we add 
one-quarter of an inch lap to the valve ; then 
the valve would open just as soon as it did be- 
fore, because we have advanced the eccentric 
to permit it to open, but it would close sooner 
by the amount of the lap, because we have 
stolen, so to speak, a quarter of an inch from 
the travel of the valve by advancing the eccen- 
tric ; therefore, if it closes sooner it cuts off the 
live steam earlier in the stroke; but, as ex- 
plained previously, it cuts off the exhaust also. 
We introduce this as an illustration of the 
uses of lap. Laps on slide valves vary all the 
way from half an inch upon a twenty-five 
horse-power engine to one inch and upward 
on high power engines ; on very large marine 
engines the lap amounts to 3" sometimes ; on 
locomotives it is usually one inch. If you 
have an engine which *^ takes steam all the 



34 

way," that is, works full stroke, you can 
materially increase its economy, and to some 
extent its power, by adding* lap to the valve 
upon the steam side ; the amount of it cannot 
be stated definitely, but must be governed by 
the size of the engine. Lead on a slide valve 
is the amount that the port is open to admit 
steam when the engine is on the dead center. 
The object of lead is two-fold: to have the 
ports and cylinder full of live steam the instant 
that the return stroke begins, and to check the 
momentum of the parts as they turn the center, 
or change the direction of motion. Now both 
the lap and the lead of a valve have an intimate 
relation to setting the valve for the distribution 
of steam, and as this will be alluded to further on 
in this series, we will say no more under these 
heads, because we shall be obliged to traverse 
the same ground, and this involves tiresome 
repetitions. 

The Pressure on a Slide Valve. 
Another defect or objection to a slide valve is 
the pressure upon it and the power required to 
drive it. This is great, though it. is not so 
large as it is generally supposed to be. Spe- 
cifically, in the case of small steam engines, 
Mr. C. Giddings, of Massillon, Ohio, made a 
dynamometer for the purpose of ascertaining 
the power required to move the valve on a 



35 

6')4" X lo" horizontal engine. The surfaces 
were not given nor the pressures, but when 
exerting 13.5 horse-power at 200 revs, per 
minute, the power expended in working the 
valve was one-fifth of one horse-power. In an 
engine of 9" cyl. X 12" stroke, with a three- 
ported flat slide valve, at 100 revs, of engine 
per minute, the power required to drive the 
valve was 7.3 per cent, of the power developed 
by the engine, which last was 11. i h. p. With 
a balanced slide valve on the same engine, at 
100 revs., developing 15.6 h. p., the percentage 
of load on the valve stem was only i per cent, 
{Mechanical Engineer, page 62, voL 12, 1886). 
This adduces an argument in favor of balanced 
valves vs. plain vah es ; that is to say, the one 
is 6. 1 per cent, lighter than the other to drive, 
but the fact remains that without any balanc- 
ing but 7 per cent, of the power of the engine 
was required to drive it in a small engine. We 
do not say that this is not serious, nor do we 
think it unworthy of notice, but the fact re- 
mains that some valves require less pressure 
to work than others, owing to the manner m 
which they are lubricated and the condition of 
the seats. This last is the point we wish to 
make, for if the seat is cut the power required 
will be much greater than if it was in good 
order. Moreover, if the metal of the valve and 



36 

seat are of the same degree of hardness, the 
valve will not work so well as when one is 
harder than the other. Of course the valve 
should be the softest, for it is easy to replace 
or re-face, while the seat is difficult to get at. 
The pressure on top of a shde valve is the steam 
in the chest bearing it down. When the en- 
gine is at wx)rk there is a pressure beneath the 
valve, reacting on the under side of its face, 
for the area of the port and through it. There 
is also a back pressure from the exhaust steam 
passing through the exhaust port of the valve ; 
both of these pressures tend to reduce the 
direct pressure on the back of the valve, but to 
what extent can only be told by recording the 
facts in some particular case. The mean effec- 
tive pressure shown by cards, as existing in 
the cylinder, is the pressure acting on the port- 
area face of the slide valve. 

Stem Connections to the Valve. 
We have said previously that one defect of 
the slide valve was its liability to wear untrue. 
One great cause of this is the manner in which 
the stem is connected to the valve itself. In 
locomotives the yoke is used exclusively. We 
believe there is not a single modern locomo- 
tive built without it, the reason being that there 
are no nuts or other details to work loose in- 
side the chest. 



37 

This is of the greatest importance in an en- 
gine which is worked hard under high pressure 
constantly, but the yoke has its defects as well 
as all other mechanical devices. It frequently 
breaks, and at times cramps the valve so that 
it does n:)t seat squarely ; it cannot be got out 




Fig. 4. 
without lifting the steam chest, and it is also 
very heavy, and unless supported by the valve 
itself, wears away the gland very rapidly. 
Other common connections to valves are the 
nut in a pocket on the back, four nuts on a 
straight stem, the latter being run through a 
hole in the back of the valve, as shown in fig. 
5 ; T heads on the stem are also common, the 
T fitting in a cross in the back of the valve. 
The nut in a pocket connection is one which is 
very liable to give trouble to engineers, for it 
is easy to see, unless the nut is exactly at right 



38 

angles to the travel of the valve, that it is apt 
to cramp the valve and keep it off its seat As 
the stem is constantly wearing down the 
trouble is of frequent occurrence, and it is diffi- 
cult to detect when the engine is cold, for the 
reason that ttie valve appears to be solid on its 






I^ 






Nut 








».»i\_\ J.' A*_^ 





Figs . 5 and 6. 
seat. We have seen engines which refused 
work simply from this connection to the valve. 
Upon opening the throttle the engine would get 
steam under the valve and through both ports, 
and nothing but easing the nut in the pocket 
would let the valve down solid. Fig. 5 is the 



39 
nut and pocket connection, an.d the nut should 
in all cases be faced rounding on the working 
faces. A far better and simpler modification 
of this plan, and one we have used with suc- 
cess, is shown in fig. 6; it never fouls, and the 
nut allows the valve system to be lengthened 
or shortened without the use of jam nuts. It is 
easily put in or taken out, and fills all the re- 
quirements. 

The solid nut arrangement shown is, to our 
way of thinking, the best. Ii holds firmly if 
properly fitted up, and it is also cheap to make, 
being all lathe work. It never cocks the valve 
or binds it any way ; take it all in all, it is hard 
to find one better. These connections are the 
ones that are most commonly met with, and it 
is well to know what to expect of them. 






CHAPTER VIII. 

Valves Off Their Seats. 

Now suppose we start or try to start our en- 
gine for the first time, and on opening the 
throttle find that the engine will not mov^e, or 
will move as well one way as the other and 
without power in any direction. We know that 
steam is in the chest by the heat of it, and if 
everything was all right the engine should do 
its work; since it does not, there is plainly 
something wrong with the slide valve, and in 
nine cases out of ten it is off its seat. If it was 
simply wrongly set, the piston would go one 
way but not the other ; it would make a great 
plunge forward or backward and stop there, 
but it would not drive the crank over the cen- 
ter. A slide valve does not require much to lift 
^i from its seat, and it may occur at any time ; 
a scale blown in from the steam pipe may ^ei 
under one end and lift it enough to float the 
valve, then the steam will blow through the 
exhaust. When this is observed — blowing 
through — the remedy to be adopted is, in the 
small engines, to r^p the valve stem smartly 
with a billet of wood, when, if the connection 
is in fault, it will frequently release the valve 
and allow it to seat itself. If something has 



41 
got under the edge of the valve, move the stem 
as rapidly as possible back and forth, and it 
will work the obstruction off. If all these fail 
the only remedy is to open the chest and get 
at the valve itself. If water gets into the cylin- 
der in any quantity it is very apt to jam the 
valve stem connection by bearing up on the 
under side of the valve through the steam port; 
it may even bend the stem in small engines. 
If this happens do not undertake any hammer 
and tongs remedies, but disconnect the stem, 
heat it black hot and straighten it with a mallet 
on a block of wood. Cold iron or steel breaks 

easily. 

Valve Stem Guides. 

In most modern slide valve engines the 
steam chest is on the side— right or left as oc- 
casion demands (usually the right), and the 
stem is directly connected to the eccentric rod 
without the intervention of a rock-shaft. The 
end of the stem is flattened, or squared, and is 
carried in a guide which may or may not be of 
service; if it is in line with the direct travel of 
the valve it is, but experience teaches that 
these apparently harmless guides can make a 
great deal of trouble for inexperienced persons, 
who fancy that the stem must move tightly in 
them. This is not so; the outer end of the 
valve stem must not be tied up in any way, 



42 

but must be at perfect liberty, in order to allow 
the valve to lie flat on its seat. * The only use 
of a guide on a valve stem is to prevent the 
weight ot the eccentric rod from springing it 
downward, and to carry the weight of the 
valve stem itself; beyond this the v^lve re- 
quires no guiding, for the stem will attend to 
that. Do not, then, screw up the guide on the 
valve stem so tightly as to bind it in any way; it 
should work freely with a slight play in all 

directions. 

Governors. 

Let us leave the valve and all its connec- 
tions, including the eccentric, until we get 
further in our investigations, and look at the 
governor or throttle valve. In early days en- 
gine builders made their own governors; these 
were always the common two-ball governors 
which regulated the engine (or pretended to) by 
means of a butterfly valve, so-called, in the 
steam pipe. This valve was merely a flat piece 
of brass with a shaft through it, hung in the 
steam pipe just as a damper is hung in a stove 
pipe, and usually one of these devices fitted 
about as well as the other. That is to say, the 
throttle was so badly fitted that it did not 
answer its purpose at all, and, added to this, 
its position in the steam pipe was such that it 
defeated its own object. The valve was so far 



43 

from the steam chest that there was always a 
supply of steam between it and the main slide 
valve sufficient to run the engine at full power; 
consequently, when the load on the engine 
was reduced and the engine ran faster, the 
speed was not checked until the supply ran 
out, even though the governor had partly 
closed the throttle; then when the supply was 
worked off the engine slowed down, only to 
repeat the irregular motion at every change of 
load. Moreover, the old-fashioned two-ball 
governor was sluggish in its motions. The 
balls had to move through considerable arcs 
before the throttle acted at all; it had too many 
joints, which bound themselves tight by their 
motion, and it was so defective that it was 
cast aside for better devices. There are a 
good many descendants of the same family, 
however, still in the market, and they have the 
same inherent defects. The butterfly valve has 
wholly disappeared; at the present time no one 
makes them. Neither do engine builders 
make their own governors. Many patented 
governors for steam engines are manufactured 
by parties who make a specialty of them, and 
these makers use a simple cylindrical shell 
moving in a cylinder as a throttle valve. This 
works easily and tightly, and is a vast im- 
provement on the old gear. Its faults are 



44 

chiefly those of adjustment, and arise from 
neglect or carelessness on the part of those 
who run the engine. The parts are apt to 
wear, or else the stem gets lengthened by un- 
screwing, so that the valve drops from its 
natural position and blinds the ports. In 
caring for and repairing a governor all that is 
necessary is to see that the joints, when there 
are any (in some there are none, as in the 
Pickering), are free, the pins perfectly round 
and true, and free from burnt oil or gum; that 
the stem is straight, works freely and has no 
shoulders on it from working in one place 
constantly, and that the valve is in its proper 
place when the governor is geared up. 
Running with the Sun. 
There are a great many persons in existence 
yet who put faith in traditions, and who will 
gravely assure one that such or such a ma- 
chine does not work properly because it does 
not **run with the sun." This is a notion 
that is firmly beHeved in by many who have 
(aith, but no reasoning power. The sun has 
no influence upon, or any connection with 
machines made by man, with the sole excep- 
tion of sun dials, and any machine which is in 
order will just run as well ** against the sun" 
as ** with the sun." Therefore, let no person 
impose upon you by telling you that the rea^ 



45 

son a bewitched o^overnor does not work is be- 
cause it runs against the sun. Suppose the 
engine stands east and west, how can it run 
against or with the sun ? We used the ex- 
pression ''bewitched governor" in a figura- 
tive sense only, but let no engineer ever give up 
the search for a cause of bad working in a de 
fail. It may be hidden, but it can be found 
by searching. There is always a cause for ir- 
regular action in all machines. 




CHAPTER IX. 

Eccentrics and Connections, 

The office performed by an eccentric is to 
move the valve to admit steam at alternate 
ends of the cylinder. The eccentric is simply 
a wheel hun^ out of its own center. Its own 
center is a point equi-distant from the circum- 
ference. If hung on a shaft in this way it 
would have no other motion than a true rotary 
or concentric motion around the shaft, the 
same as a flywheel has on its shaft. Being 
hung out of its center, it has an untrue motion 
— an eccentric one — from which it takes its 
name. This explanation may sound somewhat 
puerile to experts, but there is an idea in the 
minds of many that an eccentric has some 
mysterious action which makes it especially 
fit for driving steam valves. We have been 
told by some that the eccentric ran fast and 
slow without reference to the speed of rotation 
of the engine, and it h^d, for that reason, a 
''dwell," so to call it, at each end of the stroke, 
that permitted the steam to enter quickly and 
to escape freely. The "dwell'' exists, but it 
is is not by reason of any peculiarity of the 
eccentric itself, but on account of changing the 
motion of the valve frt>m forward to back. At 



47 

this period in the stroke the eccentric and all 
its connections are in line, see fig. 7, and for a 
portion of the stroke, from a to b, the eccentric 
exerts little or no effect upon its rod and the 
connections to it; in itself, however, it is mov- 
ing at the same speed it always moves at, 




Fig. 7. 



which speed is that of the engine. The idea 
that an eccentric has a variable speed doubt- 
less arose from some one looking at the long 
side of it passing over the shaft rapidly, and 
comparing it with the short side, which does 
move slower than the long side, because it is 
nearer the center of the shaft. Now, an ec- 
centric is hung out of its own center just half 
the stroke of the valve, because in a complete 
revolution it will double this throw, as it is 
called. The throw of an eccentric, then, is the 
amount it is out of truth (fig. 7), or the distance 



48 

from the center of the shaft to the center of the 
eccentric. Suppose this to be ij^ inches, 
then the eccentric is said to have i% inches 
throw, and the travel of the valve is three 
inches. 

Connections from the valve stem to the ec- 
centric are of various kinds. Where the steam 
chest is on the side the eccentric rod is con- 
nected directly to the valve stem by a pin on 
the side of the stem, or by a spade handle, as 
it is called, worked on the stem itself, Some- 
times, however, as when the steam chest is 
not on the side, there is a rock shaft between 
the eccentric and valve stem. This makes no 
difference in the action of the eccentric, but 
makes some difference in the position of it on 
the shaft, as will appear later on in this series. 
Sometimes there is an idler shaft, which also 
rocks, but makes no difference in the position 
of the eccentric on the shaft from that which it 
occupies when directly connected. The con- 
nections are in all cases merely carriers or dis- 
tributers of motion between the eccentric and 
the valve itself, and need not be considered as 
affecting- the motion, except as hereafter ap- 
pears. 

The Crank Pin. 

There is no more important adjunct of an 
engine than the crank pin, for through it all the 



49 
power of the steam is transmitted. This state- 
ment does not refer to its office wholly, but to 
ils condition and its construction. In most 
cases engineers are powerless to alter this with- 
out going to a great deal of expense, but they 
can at all times keep it in good order, and in 
such condition that the friction of it is reduced 
as much as possible. Engineers worthy of the 
name take the greatest pride in having this de- 
tail free from every scratch or flaw on its 
w^orking face, and, above all, never allow it to 
get more than hand-warm ; that is, about the 
heat of the human hand. It should not heat at 
all if properly attended to and when properly 
proportioned in the first instance, but there are 
many proprietors who run engines much be- 
yond the power they were intended for, and 
when this is the case the crank pin is liable to 
suffer first. Crank pins heat from several 
causes. When they have always run cool 
with the normal load on the engine, and de- 
velop a tendency to heat when the load is in- 
creased, the cause is too much pressure per 
square inch of surface ; this forces out the oil 
and brings the boxes into forcible contact with 
the pin, so that heat is engendered. A remedy 
in cases like this is to use a heavy oil, or a 
grease composed of equal parts of plumbago 
and tallow or lard. This finds its way into 



so 

the most minute ridges or imperfections in the 
bearing:, and keeps the surfaces apart ; it is a 
very excellent lubricant to use upon an over- 
loaded engine. More generally, however, 
crank pins heat from constant tinkering with 
.the connecting rod end. An engineer hears a 
pound, and arguing at once that the crank pin 
brass must he slack, drives the key down, with 
the result of heating the pin. Now this matter 
of adjusting brasses on crank pins and on other 
bearings is an important one, not so well un- 
derstood as it should be. In a great many 
cases the brasses are not properly fitted when 
they leave the shop, and are liable to cause 
trouble from that fact. High speed engines of 
the best class are properly made, for the build- 
ers of them are men of experience, but there 
are some persons who, as soon as they get 
charge of such engines, proceed to '* relieve'' 
the brasses in the wrong place, so that they can 
key them up. Now what is good for a high 
speed engine is good for a slow speed engine, 
and every bearing, no matter what its office, 
should bear *' brass and brass," as the term is, 
and shown in the diagram at a — not as shown 
at d. The brasses should butt solidly and fairly 
together, and the pin should work easily inside 
of them. Then it will have merely the friction 
of work, and not the friction due to the work, 



51 

with that due to the pressure of the key added. 
Many persons hold that no more pressure can 
be put upon a crank pin than that due to the 
work, and unless the pressure of the key or 
bolts exceeds that of the work, it adds nothing 
to the labor of the bearing-. Those who hold 
this view are requested to try the experiment 
of driving in the key a little on a bearing which 
shows signs of heating. They will speedily 

-A 




Fig. 8. 
relinquish their theory. Another cause of heat- 
ing of crank pins and other bearings is faulty 
workmanship. The brasses do not bear fairly or 
seat squarely and while they appear all right to 
the eye they are not all right to the bearing, 
which speedily gets warm over the matter. A 
crank pin brass must seat squarely on the end 
of the connecting rod, and the rod end itself 
must be square. If the key, when driven, 



52 

forces thfe brass to one side or the other, and 
twists the strap on the rod so that its sharp 
edges can be felt on the side, it will draw Itie 
brass a-cock-bill on the pin, and make it bear 
the hardest on one side of it, reducing the area 
for working by the amount it is out of truth. 
The same condition of things is true of the 
main bearing. If the brasses do not bed fairly 
on the bottom of the pillow block casting, and 
do not go down evenly, without springing in 
any way, they will not run as they should. It 
matters not whether an engineer is a workman 
or not, in regard to his seeing these things. 
When they are pointed out to him, he can, and 
that is our reason for directing attention to 
them. If he knows where the fault is he can 
find men to remedy it. 

Another cause of heating in bearings is too 
much surface in contact that is merely friction- 
al. This is best explained by fig. 9, where all 
the work of transferring the power of the steam 
is done upon the surface of the pin, which is 
shown in section. All the bearing beyond 
this is of no service, but is a positive injury if 
if touches the pin, for it merely rubs and wears, 
without doing any good. Engineers then 
** clear'' the brass on its sides as shown in fig. 
9, for all bearings, whether those of the main 
shaft or elsewhere. We say " clear" the brass 



53 
which means that it is to be just free, or so that 
it does not touch; not as shown in the diagram, 
where it has to be exaggerated to be seen at 
all. This clearance has another value, that of 
permitting the oil to stay on the pin, and to 
cover it at all times. This end is also furthered 
by cutting X grooves in the brasses, but this 
practice we have never been greatly in favor 
of, except in solid brasses which oscillate, or 




Fior. 9. 
do not completely traverse the pin. For these 
last oil grooves are essential, inasmuch as 
when they are hard worked the oil is not dis- 
tributed as it is in a complete revolution, and 
they are very liable to cut from want of access 
of the oil to all parts. Oil grooves, however, 
have the disadvantage of retaining dirt which 
may find its way in, they invite fracture, and 
they reduce the bearing surface. They are not 
to be used indiscriminately. 
No greater annoyance can happen to an en- 



54 

gineerthan to have bearings heat beyond a cer- 
tain degree. When shafts run hand warm it is 
no great matter, but it is better to have them 
quite cold, for then they do not give any anxi- 
ety lest they should become hot. Heat of any 
degree about a bearing is certain evidence of 
friction; what causes it is for an engineer to find 
out. If all bearings about an engine were ab- 
solutely parallel to each other, perfectly round, 
smooth, and true, of ample area and properly 
lubricated, they certainly w^ould not give any 
trouble, but it is because some of the qualities 
above mentioned are lacking that they do give 
trouble. Want of proper materials in contact 
is also a cause of heating; dirty lubricating oil, 
or that which is too light in body for the work 
to be done, will also work badly for an en- 
gineer. Badly designed engine frames cause 
heating of main bearings by springing; settling 
of foundations, and badly fitted bearings do the 
same. For example, if on taking up a bearing 
that heats, the brass is found to bear as shown 
by the shaded lines in figure lo, the remedy 
is to scrape away the shaded portions so as to 
have a fair bearing, but before doing this an 
engineer should be sure that the fault is in the 
brass and not in some part of the pillow block, 
or other detail that holds the brass in its place. 
Brasses are usually made as light as possible to 



55 

save material, and it is a very easy matter to 
spring them in fitting up. If they are so sprung 
it is of no use to refit the bearing itself, because 
that does not cure the trouble. It will continue 
to bear badly until worn out if the cause which 
springs it is in existence. Get the spring out 
first, and then refit the bearing, and there will 
be no trouble. Chronic heating in brasses is 
almost always caused by this defect — badly 

71 




fitting brasses. Another cause is, as stated, 
dirt, pure and simple. This need not be like 
sand or gravel to give trouble. Sometimes 
dirt gets in with the oil. All oil should be 
strained through a cloth, no matter how clear 
it looks. There is a great deal of dirt in lubri- 
cating oil of the average quality, as engineers 
find who strain it. Dirt also gets in through 



56 

carelessness. Any work done on a floor over an 
engine shakes dirt down upon it at some time 
or other, and all floors over engines should be 
ceiled absolutely dust proof by laying paper 
between the planks. Imperfect lubrication is 
also a source of difficulty with bearings, 
though, as a rule, there is oftener too much oil 
used than too little. 






CHAPTER X. 

Adjustment of Bearings. 

Another, and perhaps a by far too common 
cause of trouble with bearings, is improper ad- 
justment of them; that is to say, to the friction 
of the load proper is added the friction caused 
by excessive tightening- of the bolts and nuts, 
or gibs and keys. It is easy to see, we think, 
that the office of a bearing is simply to hold the 
detail in its place while it is at work. A gib 
and key will not only do this, but it will also 
permit an engineer to take up a bearing as it 
wears, in other words, make it larger or smaller. 
Now, this is not a virtue, by any means, but a 
defect, for it gives an opportunity for careless 
men to do mischief through want of judgment. 
Men who do not think, so soon as they hear a 
pound or a noise about an engine, immediately 
accuse some bearing and go at it with a ham- 
mer or a wrench, and tighten it up. Bearings 
on an engine which is in line and in good or- 
der seldom require any attention of this kind. 
It is really surprising how long they will run 
without being touched in any way. We know 
of stationary engines doing heavy duty which 
have not had the crank-pin bearing touched in 
three years, and from which not a sound 



58 

comes. It IS the same with the main bearings; 
where everything is in good order they do not 
want any tinkering, and the best evidence an 
engine can give that it is not in order is noisy 
action. We know of some stationary engines 
that run at high speeds (240 revs, per minute 
constantly), yet no one would know they were 
running if they turned their back upon them. 
They are actually and absolutely noiseless. 
Not one penny has been spent upon them for 
repairs in over two years, and no tinkering of 
any kind has been done upon them. Facts 
like these prove our assertion that perfectly ad- 
justed bearings and good workmanship com- 
bined will run satisfactorily for long periods. 
Unfortunately, not every engine is the best of 
its kind, and engineers can not always control 
the conditions. In other words they can not 
rebuild the engines, and we are willing to ad- 
mit that there are some engines which it is 
very hard to *^get the pound out of.'' Let it be 
borne in mind just what the office of a bearing 
is, however, and much can be done to lessen 
the annoyance of pounding. Reference will be 
made to this further on in this work, as some 
of it is due to faulty valve setting. 
The Valve and Gearing. 
Having now gone from the cylinder head 
to the main shaft of our engine, and briefly re- 



59 
viewed the principal details, let us go back to 
the steam chest again and look at the slide 
valve and the valve seat, as shown in fig i. 
Let us compare them and see what relation 
they bear to one another. The office of the 
valve is to open and close the ports alternately, 
as we all know, and if it is rightly made, it will 
do this unfailingly, but it too often happens 
that it is not rightly made, but is simply a cast- 
iron box stuck in the steam chest anyhow, as 
we may say. Sometimes, in small shops (and 
in large ones for that matter), foremen get 
notions in their heads that a slide valve was 
never made until they got one up, and the man 
who is afflicted with an engine of this kind has 
a big bill for fuel. At other times engineers 
them*selves get notions as to exhaust lap and 
exhaust lead, and cut away or add to slide 
valves that were in perfect order before they 
meddled with them. We have no theories of 
any kind to propound, and no hobbies to ride, 
and shall illustrate, therefore, only the usual 
defects and the methods of curing them, leav- 
ing every one to adopt or reject them as they 
see fit. 

Figs. II, 12, 13, show the slide valve in 
various positions: the first one at mid-stroke, 
where it covers both ports; the second with 
lead, or just opening the port; and the third 



6o 



with the port full open. This valve is shown 
as having" line and line exhaust, that is to say, 
without lap on the exhaust side. The result is 
shown by looking at a, fig. 12, where the steam 
is passing out, as shown by the arrow; it has a 
free exit, to the extent of half the steam port 




nearly, when the crank is nearly on the center, 
but the exhaust began to open before the piston 
arrived at the end of its stroke. This is just 
the point where, it is claimed by those who are 




I 

I 



62 

in favor of inside lap on a slide valve, that an 
error is made, because it lets the steam escape 
before it has done all the work that it can. In 
some measure this is true, because every inch 
that a piston travels under pressure gives 
power, but the diagram, fig. 14, shows, to our 
mind, that the steam, on the last quarter of the 
piston stroke does very little work indeed. It 
is at a comparatively low pressure, having 
been expanded through the cylinder, and the 
force exerted by it is spent upon a crank whose 
radius is shown at a, fig. 14, and not in a direct 
line, or at right angles with the line of motion, 
but at a very obtuse angle, as shown by the 
dotted lines, so that the effort to turn the crank 
is absorbed to a great extent before it reaches 
the shaft itself. Suppose we do add inside lap, 
as shown by the dotted lines at 3, figs. 12, 13, 
to the extent of half the steam lap, then we re- 
tain the steam in the cylinder until the piston 
has completed its stroke; we follow it up 
with spent steam until it begins the re- 
turn stroke; we get a full exhaust of 
the spent steam through the steam port, but 
we lose nearly half the area of the exhaust port 
in the valve seat, so that, as shown at^, fig. 13, 
which ever plan we adopt, whether line and 
line exhaust, or lap on the exhaust side of the 
valve, we have to sacrifice something, and the 



63 

general sentiment of experienced engineers is 
in favor of a line and line exhaust. The first 
thing an old engineer does who finds a valve 
with inside lap on it, is to chip the lap off, and 
swear some at the man who put it on. 

In saying this, however, we must qualify it 
to this extent: that there may be cases where 
line and line exhaust is inadmissible or unde- 
sirable by reason of the proportions of valve 
face and steam ports. Our diagram shows the 
usual proportion of good practice. This is, 
that the bridge or metal between the two ports 
(steam and exhaust) is equal to the width of 
the steam port, and the exhaust is twice the 
WMdth of the steam port. Not all valve faces 
and steam ports are so made, and the change 
involves some changes in valve construction 
and operation of the engine; but it is manifest 
that we can not treat upon this exhaustively in 
this work. The best arrangement for the ex- 
haust must be determined for each engine by 
an indicator, which is the only friend an en- 
gineer has to tell him w^hat is going on where 
he can not see directly. 

These examples, it is understood, all exhibit 
the action of a slide valve when working at full 
stroke, or without cut-off, and from them it is 
easy to see that the evils of choking the ex- 
haust and wiredrawing the live steam (that is, 



64 

admitting it through a very narrow opening in 
the valve face), are increased when steam is 
used expansively, hence the unfitness of a slide 
valve for an automatic cut-off is readily under- 
stood. It is especially seen in locomotives, 




where, with a short cut-off, used at high speeds, 
the exhaust is actually punched out by the pis- 
ton, for it begins to be compressed at half 
stroke, as shown by this card, fig. 15, which 
was taken from a locomotive on a fast run. 



7^' 



%W 



CHAPTER XI. 

Setting Eccentrics. 

This detail is one of the simplest duties an 
engineer has to perform, but it is sometimes 
made a very mysterious matter. Elaborate 
preparations are made ; much peering into the 
steam chest takes place, and the chief perform- 
er looks very wise. There is no occasion for 
performances of this character, for the whole 
operation from first to last should not consume 
ten minutes, and a man of experience can set 
an eccentric at the first turn over, generally, 
after the valve is squared. This last means 
that the valve shall open both ports alike. 
Squaring the valve also makes the eccentric rod 
of the proper length, and until the valve is 
squared no setting of the eccentric can be done. 
Take notice that it is the eccentric which is to 
be set, not the valve. The valve occupies 
various positions on the valve seat, but the ec- 
centric has a fixed position on the shaft for 
each particular valve. In one work on the 
slide valve the operation of setting an eccen- 
tric occupies two pages of directions, and end- 
less a b'Sy c d's, xys, and other letters of refer- 
ence which are wholly useless. We never 
found any italics on valve stems, or on eccen- 
trics ourselves. Moreover, much time is spent 



66 

with trams, etc., in getting the exact mathe- 
matical center, or putting the crank pin exact- 
ly midway in its orbit, all of which is useless 
work. An eccentric can be set without any 
heavy flywheel to turn, or connections to drag 
hither and yon. Every part of the working 
gear not actually connected with the eccentric 
and valve should be taken off, for it only cre- 
ates friction for nothing. 

The Actual Operation. 

Take out the crank pin (unless it is riveted 
in) and run a line through the cylinder. 

Put on the eccentric strap and connect it to 
the valve stem, just as if it was under steam. 

Now turn the crank shaft the way the engine 
is to run by any means that will turn it. If 
the flywheel is on use that for a lever. 

Look in the steam chest and see if the valve 
opens both ports equally. 

If it does not, shorten or lengthen the stem 
half the difference, until the eccentric moves 
the valve properly. 

Now put the crank on its center by the line, 
and move the eccentric around on the shaft 
until it opens the port slightly, and stands as 
shown in the diagram, figure i6, at i. 

Turn crank i on the other center, and the 
valve will show more or less off of the position 
it had when on the other center. Divide the 



67 

difference by leng-thening or shortening the 
valve stem half the amount of error (for what 

ii 




is taken off one end is put on the other in one 
revolution), and the work is done. 



6S 

There is no occasion to have the connectnigf 
rod or the piston in ; they have nothing what- 
ever to do with setting the eccentric. This 
should be done the first thing after the shaft is 
in place, not when the details are all in. Once 
set, the eccentric is always set, unless it is 
shifted by chance. When it is once in place, 
it should be marked with a chisel, so that it can 
be put back if accidentally slipped 

There are a good many who will object to 
this method of setting an eccentric, because it 
is out of the usual way; but it is as exact in re- 
sult as any other way. There is no use in 
fussing w^ith trams ^o ^et the exact mathemati- 
cal center of the flywheel, because (unless the 
valve has no lap) no engine takes steam on the 
exact center. It always has more or less lead, 
the amount of which must be finally adjusted 
by an indicator for the work to be perfect. It 
will be seen by figure i6 that the eccentric is 
slightly in advance of the crank; that is to say, 
that its center line is not the crank's center 
line. The angle so formed is called the angle 
of advance, and the advance is m^ade to take 
up the lap and to give lead, as shown in fig. i6. 
We must here say that in all cases the valve 
will be ^'late,'' as it is called, on the back end 
steam port, and this port will not open so fully 
as the front end port. As the explanation of 



69 

this involves a diagram, which, owing to the 
limits of the page in the work, would be very in- 
tricate, and not at all clear to inexperienced 
persons, we shall not attempt one, but say that 
the error is due to the fact that a fixed point on 
- the eccentric rod in one revolution, and a fixed 
point on the connecting rod in one revolution, 
forms cycloids of diverse areas and outlines, 
and a fixed point in one is not and never will 
be coincident with a fixed point in the other ; 
the eccentric rod is always behind, varying in 
degree with the length of the connecting rod. 
If the latter was of infinite length, there would 
be no difference in the action of a slide valve 
on both ends of the cylinder, but the shorter 
the connecting rod is the greater its angle of 
divergence with the path of the eccentric rod, 
and the greater the error in the valve motion. 

Suppose we could drive a nail through the 
side of a connecting rod, and could hold a 
board up to it while the engine was running: 
then the figure described would be a cycloid, or 
egg-shaped. Now drive a nail through the ec- 
centric rod, and the figure described by it 
would be a cycloid also, but different in out- 
line and area, and the shorter the connecting 
rod the greater would be the discrepancies. 
This is, in brief, the cause of the difference in 
port opening for both ends of the cylinder, but 



70 

it affects the action not at all. There are many 
valve motions which seek to overcome this so- 
called evil, and such motions are called radial 
valve gears, for they operate the valve by levers 
instead of eccentrics ; some of them have ec- 
centrics also ; one only for both motions, for- 
ward and back. These are used chiefly on lo- 
comotives and screw propellers, and the cy- 
cloid described by the valve stem connection 
is a very close approximation to that of the 
connecting rod, so that the port openings are 
practically equal, and the cut-off is equal for 
all points of the stroke. This makes a better 
distribution of steam, and raises the efficiency 
of the whole machine to some extent ; but the 
actual values of these gears is very slight when 
compared to the cost of keeping them up, and 
their inaccessibility when in motion. The ob- 
ject of putting lead on a valve is to fill the 
ports with live steam, for one thing, and to 
check the motion of the piston gradually so 
that it will cushion on live steam. The amount 
of lead varies with the character of the work. 
Engines which run slow, say 50 to 60 revs, per 
minute, require very little, but high speed en- 
gines should have more. Say that our piston 
5s 12" diameter and the engine makes 60 revs. 
per minute; then i-32d of an inch is ample lead 
for the valve. A great deal of steam can get 



/T 



/ 



71 

through an opening of this dimension, but if 
the same engine makes 400 revs, per minute, 
then the valve should have 3-3 2ds lead, and may 
even require more. Now, the link motion, as 
most persons know, increases the lead on the 
valve as the steam is cut off. It is useful to 
bear this in mind, but we shall not attempt an 
explanation of the cause. 

This work, as its title indicates, gives ele- 
mentary instruction upon the operation of en- 
gines and boilers, and we do not mean to go 
outside of that and make it a medley of several 
different branches of an engineer's profession. 
Moreover, if we attempted this line of instruc- 
tion, we should only repeat the researches of 
others. Those who want a treatise upon the 
link motion and its operation should purchase 
^^ Link and Valve Motions,'' by Auchincloss, which 
is a standard work, explained in the clearest 
manner, and fully illustrated. 

Setting the eccentrics of a link motion is 
precisely the same operation as that of any 
other, with this difference only : that both 
rods, back and go-ahead, must be adjusted for 
length before the eccentrics are set, for a 
change in one affects the action of the other. 
Suppose, for example, that we undertake to set 
the go-ahead side before the backing side is 
corrected for length. We get the go-ahead 



73 

wheel on all right, but when we throw the 
backittig side in gear and set it, then we find, 
on trying the go-ahead side, that it is out. 
This is caused by the backing eccentric rod 
being of the wrong length. Now, if we have 
squared the valve for both motions, we set the 
eccentrics as shown in this diagram, fig. 17. 
This position answers only where the link is 
directly attached to the valve stem. Where a 
rock shaft is used the dotted lines show the po- 
sition of the eccentrics. 

Setting the cut-off valves of an engine is a 
very short job. Usually these valves are so 
fitted that they operate from no admission at 
all — zero, so called — to full stroke. Sometimes, 
however, they are not connected to the 
governor, but are set to cut off at some fixed 
point, say one-half of the stroke. To do this, 
or to cut off at any point of the stroke, it is 
only necessary to square the valves in their 
travel over the main valve, run the crosshead 
to the point at which it is desired to cut off the 
steam, set the valves so that they just close the 
main steam valve port, and then turn the eccen- 
tric around on the shaft until it will connect 
with the cut-off valve gear. Or, connect the 
cut-off valve gear with the eccentric and then 
turn the same on the shaft until it just closes 
the ports at the desired point. 



CHAPTER XII. 
Return Crank Motion. 

The return crank motion is the same as an 
eccentric, and is set in the same way. It has, 
however, the disadvantage that the lead can 
not be changed unless there is a slot for the pin 
a to move in, for, as will be seen in fig. i8, 
moving the return crank in or out from the 
center of the main shaft merely increases the 
travel of the valve, the lead being very slightly 
affected. 

It must be borne in mind that setting the ec- 
centrics of an engine is at best a haphazard 
operation when it is done while the engine is 
cold. Many changes lake place in the valves 
and valve motion when the engine has been 
run a while and after it has been heated 
up. Cast-iron expands materially by heat, and 
the valve gearing itself stretches, if we may so 
term it. That is to say, the strain imposed 
upon the several joints and connections make 
the actual relation of the valve and eccentric 
different from what it appeared to the naked 
eye when the steam chest was open and the 
engine was cold. 

This is one reason why it is unnecessary to 
waste time in finding ''absolute centers'' of en- 



75 

gines with a tram. All have to be corrected 
by the indicator at last, for that is the only in- 
strument we have for detecting the actual se- 
quences of the valve and valve gearing gener- 
ally. We venture to say that a good steam 
distribution, as shown by the evidence of a 
card, will bear very little relation to the ab- 
solute centers, or point of no motion of the 
crank and piston. 




Fig. 18, 



So far as setting eccentrics is concerned, 
many of them, in radial valve gears particu- 
larly, are forged solid on the shaft. They are set 
in the drawing room, and the relative lengths 
of the several rods are plotted out on the draw- 
ing board. It must be borne in mind also that 
this method of setting an eccentric, as to its 
relative position with the crank pin, refers only 
to the valves which slide on their seats, piston 
valves included; not to puppet valves, or to all 
forms of radial gears. The great majority, 
however, stand as shown in the preceding dia- 



76 

grams. The influence the valve has on the 
action of an engine is very great. As we have 
said in previous lines, the principal object of it 
is to distribute the steam properly in the cyl- 
inder at each stroke, and incidentally, to cor- 
rect or check the motion of the several parts 
at the end of the stroke. This is done by cush- 
ioning the piston on a bed of live or dead 
steam, as the fancy, or the teaching, or the ex- 
perience, of the engineer directs. If all steam 
engines were perfectly built this would not be 
necessary, but there are many defects of con- 
struction and erection which have to be com- 
pensated for, and this is generally done by 
compressing the dead steam, or admitting live 
steam in the form of lead. The crank itself is 
one of the most perfect details ever devised by 
man for gradually absorbing or taking up the 
momentum of the parts, and many first-class 
engines are at work turning their centers with 
neither lead nor compression, and are also 
noiseless in action, but this can not be done 
with the average engine, or with very high 
speed engines, so lead and cushioning, or com- 
pression, is resorted to. 

Pounding. 
One of the commonest defects of steam en- 
gines, and one that is the most annoying to 
hear, is pounding, so called. That is to say 



77 
ihni in passing the centers a noise is heard, 
which may proceed from several causes, and 
is distinctive in character for each one. These 
can not be described so that an inexperienced 
person can tell the cause of it from the noise. 
Detecting or locating natural noises, so to call 
them, or the sound caused by the natural work- 
ing of an engine, and separating them from 
noise caused by defective action, is a part of 
an engineer's duties which can only be gained 
by experience; so w^e shall not attempt it, but 
proceed to point out some which are common. 
The first we shall mention is when an engine 
is out of line. 

Take a chalk line and stretch it taut, so that 
it is absolutely straight, without sag. This rep- 
resents the center line of an engine. Now, if 
every detail is exactly in harmony with this, 
there can not be any sound from an engine. If 
the main shaft is exactly (mind what exactly 
means!) at right angles with the center line, 
and the path of the crank is exactly true also, 
if the crank pin is absolutely square with the 
center line of the shaft and revolves mathemat- 
ically exact with it, then the engine is in line, 
and the fault is not there. 

The Connections. 

Now^ look at the connections. Suppose the 
connecting rod is not properly fitted up or 



79 
keyed up, and stands off from the crank pin 
when cast loose from it, as shown in the dia- 
gram, then a noise will be heard which is 
caused by the ^'chugging" of the crosshead 
against the inside of the guides at each stroke; 
the crank pin springing the crosshead from side 
to side at each revolution. This noise is hard 
to locate when the engine is at work, particu- 
larly if the guides stand vertically and are 
V-shaped, as in Corliss engines. If it is sus- 
pected as a cause of pounding, disconnect the 
crank pin end of the connecting rod and key 
up the crosshead end tightly; then the rod will 
show for itself whether it hangs square or not. 
If it does not point fair for the exact center of 
the crank pin, between the collars, ease off on 
the back of the crosshead brass slightly, so as to 
throw the rod in the center of the collars. Try 
the crank on both centers, and if the rod shows 
off on each side, right and left alternately, then 
the main shaft is out of line and must be brought 
true. Where there is a heavy belt dragging on 
the outboard end of a main shaft it is very apt 
to haul it around materially, even canting the 
whole outboard foundation sometimes, if the 
latter is high and narrow, as it usually is. 

We have stated before that it is seldom that 
bearings are so slack as to cause a pound. The 
noise of a slack bearing is a "chuck,'' so to 



8o 

Call it, and not a pound proper, and it is of no 
use to endeavor to silence a noisy engine by 
screwing or keying up ; that only makes a bad 
matter worse. Very often pounding- is caused 
by improperly set valves, and sometimes a lit- 
tle more lead or less compression will cause it 
to work better. 

This, it must be borne in mind, is only a 
rough and ready method of finding whether 
the crank shaft is true or not. The proper way 
to do this is to take the engine apart, run cen- 
ter lines through the cylinder and the guides, and 
see whether they are in line with each other. A 
plumb line should be dropped over the exact 
center of the crank shaft, in the crank pit, so 
that the vertical line barely touches the cylin- 
der line. The crank pin should then be tried by 
this line, so as to ascertain whether it is equal- 
ly distant from it on top and bottom centers. 

Sometimes it will be seen, where the engine 
has run a long time, that the shaft needs to be 
raised at the crank end in order to bring it 
square. This is shown by the center in the 
shaft itself, by putting a square on the end of 
the shaft and allowing the blade to come gent- 
ly down to the horizontal center line through 
the cyhnder. These directions are very easily 
understood by persons who have had experi- 
ence, but those who have not, need to exercise 



8i 

care in using the square, for if the end of the 
shaft itself is not true the indications of the 
square are of no vakie. Do not undertake to 
true any horizontal shaft by a spirit level. 
Shafts are not the same size all the way ; that 
is to say, they are not true themselves, not- 
withstanding that they may have been turned 
and are apparently true. 

Another and very common source of pounds 
ing in an engine is changing the valve motion, 
or re-setting it, and overhauling the engine for 
repairs. If the valve time is changed so that 
it takes steam at a different point from where 
it formerly did, earlier or later, the pressure 
comes in a different place on the crank pin and 
shaft, which are worn to the old valve motion. 
The engine will not work then smoothly until 
the brasses are refitted. All bearings upon en- 
gines that have been overhauled are liable to 
this trouble, and it is an exceedingly difficult 
one to detect. The best way to avoid it is tore- 
bore all brasses and re-turn all bearings that 
can be so treated. The main shaft can not be, 
but the crank pin may be *' skinned over,'' as 
it is called, to its great improvement. These 
things properly belong to refitting an engine 
in a machine shop, but as it is part of an en- 
gineer's duties to know them, we have said a 
few words in that direction. 



82 

A few lines back we made a brief reference 
to lining up an engine in order to avoid pound- 
ing, but perhaps a diagram and more explicit 
directions as to putting all parts in line will be 
acceptable. An engine out of line never will 
work as it should, and as it is a very simple 
matter to have it square we shall give plain 
directions how to make it so. 

The diagram, fig. 20, shows a side elevation 
of a Corliss engine. In the crank-pit is a 
square frame made of boards, stiff enough to 
hold a line firmly without jar or tremor. This 
frame is not necessary if there are timbers 
overhead or at the end of the frame to fasten a 
line to ; the frame is only put in the diagram 
to show the process. The piston, crosshead 
and connecting rod are taken off and out of the 
engine, and a line, a, is stretched through the 
cylinder. One end of it is fastened to the cross, 
b^ shown in diagram C This cross is made 
of wood firmly fastened together and having a 
hole in the exact center of it about ^ of an 
inch in diameter, or larger than the line which 
goes through it, and the line is held by a piece 
of wire run through a loop in the end of the 
line, so that by moving the wire one way or 
the other, the line can be centered in the cylin- 
der independent of the cross. This cylinder 
line must be as fine as possible, hard-twisted 



84 

and very strong, so that it can be stretched very 
tight and have no sag whatever. Run this line 
through the cylinder, draw it up tightly, and 
then center it absolutely in the cylinder, by 
cutting sticks half the diameter of the cylinder, 
moving the crank end of the line until it is ab- 
solutely centered in the cylinder at both ends 
of it. Pay no attention to where the crank end 
of the line is ; let it go where it will with refer- 
ence to the shaft itself. Now make a tem- 
plate, B, which just fits the guides accurately, 
and draw lines through it, as at c and d. Where 
these lines cross each other is the exact center 
of the guides, and we want to know if they are 
centered with the bore of the cylinder. If the 
guides are worn much, it will be in the center 
of them, where the greatest stress comes, and 
this cannot of course be changed except at 
great expense ; but it often happens that the 
cylinder shifts, and this can be remedied by a 
good machinist. We cannot give directions 
what should be done in such a case, but must 
leave the matter to be dealt with by every one 
to suit emergencies. The guides and cylinders 
of Corliss engines are supposed to be abso- 
lutely in line when new, and the method here 
illustrated is the one used to find out whether 
they are or not. Now suppose that we have 
our line centered exactly in the cylinder, the 



85 

next thing we want to know is whether the 
shaft is exactly in the center of it. There are 
two ways to do this, and one of them is 
troublesome and expensive — the other is not. 
We show the easiest way. This is to drop the 
plumb hne, e, at the exact center of the shaft, 
so that it just clears the cylinder line, using a 
try square on the end of the shaft with a blade 
long enough to reach the intersection of the 
two lines, so as to verify them ; try the square 
on both sides of the line, front and back, and 
the centre of the shaft will be accurately lo- 
cated. If the front end is low, the remedy is 
to raise it, of course, but before moving the 
shaft forward or back by the quarter brasses, 
the crank must be tried on the four quarters of 
its circle of rev^olution. This will show at 
once where the shaft stands with reference to 
the horizontal line, a, and the vertical line, e. 
Turn the crank over until it comes up to the 
cylinder lines, as in figs. 21 and 22, If the 
crank-pin is exactly midway of the collars with 
the line, it is right on that center. Now try it 
on the other center, and it will perhaps stand 
off; if it does, the remedy is very plain. Now 
spring the cylinder Hne on one side so that the 
pin will pass it, and try the crank-pin on the 
vertical line, e (fig. 22)\ if it stands in toward 
the cylinder line, the center of the shaft is low 



86 



and must be raised. Try it on the bottom half 
center also, and rectify it according to what the 
line says. This method of lining up an engine 
will cause the crank to revolve in a truly verti- 
cal plane, at exact right angles with the bore 
of the cylinder. It makes no difference what 



CYLINDER LINE 



I n 



Figr. 21 & 22 



kind of an engine it is, the method is the same 
for all, and any man of ordinary intelligence 
can put his engine in exact line if he follows 
these directions. 
This is not to say, however, that all pound- 



87 

ing will cease so soon as he has done so. We 
have fully adverted, in former chapters, to the 
causes of this, and need not repeat it. For the 
rest, time and experience can alone make an 
experienced engineer. No man can learn from 
a book exactly what to do with an engine to 
make i^ perform to the best advantage. 

We have said nothing in this work as to the 
lubrication of an engine, but this is an impor- 
tant mi>tter, and should be performed automat- 
ically. No one should use a squirt-can about 
an engine except for temporary use. There 
are various devices in market for feeding oil or 
grease to engines, and most of them are good. 
Sight feed lubricators are essential; no one now 
uses tallov/ or other animal fats. These last 
destroy casMron most rapidly. We leave this 
matter to the discretion of those in charge. 






CHAPTER Xril. 
Making Joints. 
Joints about engines are, in the best prac- 
tice, scraped or ground iron and iron, but in 
most machines they are made by interposing 
s'.ieet-rubber, or patented compositions of it, 
which answer the purpose fully. There are a 
number of very good materials for this pur^ 
pose on the market ; some engineers use one, 
some another ; while for metallic joints under 
high pressure the corrugated copper disks 
used are unsurpassed. These last can be used 
over and over again, and will not blow out or 
leak under any pressure. Where it is not pos- 
sible to obtain these goods, a very good joint 
can be made with the wire-cloth used for mos- 
quito-net frames. Cut this to the size required, 
and make a very thick paint with red lead and 
boiled oil ; daub this over the surface of the 
cloth and screw it up tight; it will never leak 
or blow out, but it will be hard work to break 
the joint if it is suffered to remain for a length 
of time. If no cloth is handy, a single copper 
wire, say a scant eighth of an inch in diameter, 
will make a tight joint. Cut the wire the right 
length, stick it in a fire and heat it red-hot and 
plunge it into cold water. This will make it 
as soft as lead, so that it will flatten under the 



89 

bolt pressure and fill all inequalities of surface. 
For face joints, like steam chest bonnets, hot 
or cold water pipes, heavy packing- or drawing- 
paper makes an excellent joint. Soak it in 
boiled oil and put it right on ; the heat will 
harden it into a parchment-like substance which 
is very serviceable. For permanent joints, like 
those in water-pipes under ground, or where 
they never have to be broken, a rust joint, so 
called, is the best. This can be made only 
where the castings are fitted for it in the de- 
sign — that is, with a wide channel all around 
to receive the joint. A rust joint is made of 
fresh, clean cast-iron chips or borings which 
have no grease upon them. They are mixed 
with sal-ammoniac water and driven tightly 
into the space between the pipes, where the 
boring-s soon rust into a solid mass. Putty 
joints, so called, are used chiefly on cold-water 
pipes, about the feed pump, and may be used 
on hot-water pipes as well, if suffered to get 
hard before being put under heat and pressure. 
The putty is made of dry red lead and white 
lead mixed with oil, kneaded together to a 
stiff dough. It must be beaten with a mallet, 
and the stiffer it is the quicker it sets. It hard- 
ens into a mass as solid as a brick in time. 

All these materials are only for exceptional 
use — that is, where the usual rubber or other 



90 

gaskets can not be had, for these last are far 
more convenient than any just mentioned. In 
all cases where rubber joints are used they 
must be chalked or rubbed with a good black 
lead; this prevents them from sticking to the 
surfaces in contact. Joints should, in all cases, 
be made as long before their use as possible, 
so as to give them a chance to set before 
pressure is put upon them. 

Packing the rods of steam engines is a sim- 
ple matter, but simple as it is it requires judg- 
ment and good sense. Like every other duty 
about a steam engine, it needs to be properly 
done In order to work satisfactorily. Very 
many have an idea that the packing in a stuff- 
ing box must be jammed in as hard as it will 
go to prevent steam from leaking out, or what 
is just as bad, air leaking in when condensmg 
engines are used. The reverse of this is true. 
There is no occasion to break studs and strip 
nuts on stuffing boxes to make a piston rod 
steam tight, but this very thing has been done 
by inexperienced persons. When a piston rod 
of any size can not be kept steam tight by 
moderate pressure on the packing, there is some- 
thing wrong with the stuffing box itself, and this 
trouble in old engines, and in some new ones, 
too, will generally be found in the bottom of 
the stuffing box where the rod passes through 



91 

the head. Too often this opening is made too 
large; in the case of old engines the piston rod 
has worn it oval by bearing on it. The remedy- 
is to make a brass collar, or even of lead, which 
fits the piston rod nicely, and is one-eighth of 
one inch smaller than the stuffing box itself, or 
so that it is a loose fit. Put this in the bottom 
of the box, and a few turns of packing on top, 
moderately compressed, will keep the rods 
tight. As to the packing itself, use metaUic 
packing where it is possible. There is no com- 
parison between it and ordinary hemp pack- 
ing used before there vras any metallic pack- 
ing. This last is always tight on good rods 
and runs with very moderate friction. It never 
needs screwing up or any other attention than 
to keep it in good working order. When metal- 
lic packing can not be had, an excellent sub- 
stitute for it can be found in hemp gaskets 
braided firmly into a square, and thoroughly 
saturated with plumbago; that is blacklead. 
Do not make the mistake of using stove polish 
on gaskets because there happens to be plum- 
bago in it. This quality is full of grit from the 
clay in it, and will badly score any rod to which 
it is applied. Some engineers use one thing 
and some another. There are various kinds of 
packing in market made from woven material, 
india-rubber, etc., etc., and engineers in large 



92 

towns can have a variety to select from. The 
principal thing is, as has been said, to havethe 
stuffing box itself in good order; then very- 
little compression is needed. It would sur- 
prise many who have never given the matter a 
thought to see what resistance to motion a rod 
two inches in diameter only, can offer when 
packed tightly. 




^^^^"(^^;' 



f 



CHAPTER XIV. 
Condensing Engines. 
Thus far we have given attention wholly to 
engines which exhaust into the air, high pres- 
sure engines so called, or those which do not 
condense the exhaust. Condensing engines are 
sometimes called *'low pressure" yet, but this 
is a term which is no longer applicable. It was 
used in the early days of the steam engine, 
when pressures were low, five and six pounds 
above the atmosphere. As a knowledge of 
boiler making increased, and higher pressures 
were available, the condensing apparatus was 
discarded as costly and cumbrous, and engines 
were made to exhaust into the air at higher 
pressures. To distinguish them from condens- 
ing engines^ the terms high pressure and low 
pressure were used, but there is no longer any 
fitness in the appellation, for condensing en- 
gines will work at any pressure. The chief 
feature, then, of a condensing engine is that it 
exhausts into a vacuum instead of against the 
pressure of the atmosphere. Every one knows 
that this last plugs up the exhaust pipe with a 
pressure of 14.7 pounds upon every square inch 
of its area. All that the condensing engine 
does is to remove the plug and give a free exit 
to the exhaust. This is done by creating a 



94 

vacuum in a closed chamber called a con-^ 
denser. Every one, even those with h'ltle or 
no experience, knows this, but not all know 
what a vacuum really is, or why and how such 
a state of things is possible. We can not say a 
vacuum exists, for it is not a thing. It is, in 
fact, nothing; it has no existence. A vacuum 
is simply absolute space, devoid of any fluid, 
solid or gas. It can be obtained in two ways: 
by mechanically pumping the air out of any 
tight vessel, or by admitting steam to it and 
throwing cold water in upon the steam. With 
steam engines this is the usual way to obtain a 
vacuum, and the philosophy of it is very easily 
understood by what follows: Suppose we have 
a cubic inch of water; that is a block of water 
one inch square every way. Now, if we change 
this into boiling water (212°), and let the steam 
from it into a tight chamber one foot every 
way, t^e steam will fill the chamber and be at 
atmospheric pressure in it. Now, if we have a 
pipe to this chamber, and run cold water in so 
that it strikes the steam in a spray, the steam 
will be condensed and fail to the bottom in the 
form of water again, the air and condensed 
steam falling together. Above this water 
there is a vacuum more or less perfect; but to 
make it an absolute vacuum we must remove 
the water of condensation and whatever air 



95 

there is remaining-. To do this a pump is 
necessary, and it is always present in con- 
densing engines. It is called an air pump, and 
in action it removes the air and water of con- 
densation from the condenser, leaving a more 
or less perfect vacuum, into which the engine 
exhausts. This operation goes on continually; 
the engine is always exhausting into the con- 
denser, the cold water is always condensing 
the steam, and the air pump is constantly re- 
moving the water and mist held in suspension. 
To some this operation is a very complicated 
one, and many engineers say they can readily 
manage a high pressure engine, but do not 
know anything about a condensing engine.. 
There is no reason why they should not un- 
derstand the one as well as the other, for there 
is nothing in a condensing engine beyond the 
capacity of every intelligent man. The two 
evils to be guarded against in a condensing en- 
gine are air leaks and heat in the condenser. 
Look out for these, and there will be no trouble 
in maintaining a vacuum. 

Since we have seen that a vacuum is abso- 
lute space, it is plain that if air leaks are pres- 
ent the vacuum will be impaired to just the 
amount that the air leaks in beyond the capa- 
city of the air pump to remove it. If the con- 
denser is not cold the steam will not be con- 



§6 

densed quickly, and if the water of condensa- 
tion and the vapor are not also removed, there 
will only be a partial vacuum, for the water of 
condensation is not absolutely cold, but at 120 
to 140 degrees, and gives off vapor which also 
injures the vacuum. This is, in as few words 
as possible, the detail of a condensing engine, 
and it does not seem a formidable affair. 
There are two kinds of condensers in general 
use — the jet or absolute contact condenser, 
and the surface or indirect acting condenser. 
The first is simply a cast-iron vessel, usually 
round, as best adapted to resist the pressure of 
the atmosphere, for it must be remembered 
that the pressure on a condenser outside is 
many tons in the aggregate. (A condenser 
only 40" diameter and 72" long, under a perfect 
vacuum, has over 37^ tons total pressure on 
the outside, tending to crush it.) Into this 
vessel cold water is run through a perforated 
nozzle; when the water strikes the steam the 
latter is condensed and both the injected water 
and the condensed steam fall to the bottom of 
the vessel. The surface condenser is exactly 
the same as a common tubular boiler. The 
steam enters outside of the pipes (or flues) and 
the condensing water goes through them. The 
exhaust steam, therefore, does not strike the 
water directly, but is merely received upon a cold 



97 

surface, and the water of condensation, only, 
falls to the bottom of the condenser; the con- 
densing water passes away constantly through 
the pipes, or flues, and does not mingle with 
the condensing steam. This method gives ab- 
solutely pure water for the boiler feed, except- 
ing only the foreign matters which may enter 
with the steam. Surface condensers are used 
chiefly upon ocean steamers, where they are 
indispensable, as they furnish fresh water for 
the boilers. In long voyages they are a neces- 
sity, and the greatest care is taken to avoid 
steam leaks, for this means a reduced supply 
to the boilers, Surface condensers also supply 
an immediate vacuum at the first exhaust of 
the engine. A circulating pump keeps cold 
water going through the tubes constantly, so 
that as soon as the exhaust steam strikes it it is 
condensed, and the main engines ''take hold," 
as it is called. This is not always the cage 
WMth a jet condenser, in which the vacuum is 
not very good for two or three revolutions. A 
vacuum is a vacuum, however obtained, and so 
long as one is produced that is the main thing. 
A loss of it is a loss of power, for the resistance 
of the atmosphere being removed from the ex- 
haust side, the weight of it is added to the pres- 
sure on the piston. Thus, if the steam gauge 
shows seventy-five pounds, the actual or abso- 



98 

late pressure is 75x15, or 90 pounds. From 
this aspect we can readily see why engineers 
are sensitive about the condition of the vac- 
uum, w^hether it is full or only partial. 

The first mechanically made vacuum of 
which we have any authentic record is that of 
Torricelli, an Italian experimenter, and of Otto 
Guericke, a German experimenter. Which of 
these was the pioneer vacuum maker history 
saith not. Otto Guericke, of Magdeburg 
Germany, invented the common air pump, used 
in philosophical experiments, in 1654. He first 
tried, by filling a barrel full of water and pump- 
ing out the contents from the bottom, to obtain 
a vacuum above the water, but the barrel was 
not air tight and the experiment failed. He 
then made an ordinary metallic pump and ob- 
tained a vacuum. To show that air was a fac- 
tor in the work of the world, and that w^e are 
surrounded by an atmosphere under pressure, 
he made a pair of brass hemispheres, which 
had a ground joint in the center and a cock in 
the stand at the bottom of them. He connect- 
ed his air pump to these, and exhausted the 
air from the globe, and then hitched fifteen 
horses to an eyebolt in the upper hemisphere, 
but they were unable to pull the upper half off 
of the lower. This demonstrated conclusively 
that the atmosphere had pressure, for upon 



99 

openings the cock and letting air into the hem- 
ispheres again, the balance was restored and 
the hemispheres fell apart. The first actual 
measure of the weight of the atmosphere is due 
to Torricelli, also about the middle of the seven- 
teenth century. 







CHAPTER XV. 
ToRRicELLi's Vacuum. 
This was by reason of a suggestion from the 
Duke of Tuscany, who, having dug a very deep 
v^ell, proceeded to pump it out. He found, 
however, that he could not raise water over 32 
feet, and he must have had a pretty good pump 
to do that. Not succeeding in getting water 
the Duke consulted Galileo, the famous philos- 
opher who discovered the motion of the earth. 
This water problem was too much for him, and 
he gave it up. Shortly before Galileo died he 
gave the puzzle to Torricelli, who began to 
work with mercury as a basis of comparison of 
the relative weights of the pressure of the at- 
mosphere. Now mercury is fourteen times 
the weight of water, and Torricelli argued that 
if the atmosphere would support a column of 
water 32 feet high (as it was proven it would 
in the case of the pump before referred to), it 
would also support a column of mercury one- 
fourteenth the height of the water, or 28 inches. 
To test this he took a glass tube, sealed at one 
end, and filled it full of mercury, displacing all 
the air therein. He then closed the open end 
with his finger and inverted the tube in a basin 
of mercury, when the mercury in the tube fell 
and settled, as he supposed it would, at 28 



lOI 

inches, leaving a vacuum in the upper part. 
Torricelli did not live long enough to do much 
with his discovery, but another philosopher, a 
Frenchman, Pascal by name, took it up and 
carried the experiments further. It occurred to 
him that if at the surface of the earth the at- 
mosphere supported a column of water 32 
feet high, at great elevations from the surface 
it would not support so much, because the at- 
mosphere is rarer, or less dense ; so he took 
the mercury column up on a high mountain. 

Proof of Atmospheric Pressure. 

At the top it registered only 25 inches, while 
at the bottom it was 2S inches. At other levels 
between the bottom of the mountain and its 
top he found varying registers on the mercury 
column, so it is established by inductive rea- 
soning, supported by experiments, that at the 
surface of the earth water will rise in a perfect 
vacuum 32 feet, supported of course by the 
pressure of the atmosphere, for the vacuum it- 
self has no powei whatever; it is as stated pre- 
viously, merely a space which offers no resist- 
ance, therefore, water or air rushes in to fill it. 

No Power in a Vacuum. 

It is important for engineers to know these 
facts because there are still a great many who 
are not aware of them, and suppose that a vac- 



102 

uum has some power in itself or that it has an 
existence as a force because it is measured on 
a gauge. This last is an error. Vacuum is not 
measured on a gauge., but atmospheric press- 
ure is. We can not measure a nonentity and 
we must insist that engineers bear in mind that 
a vacuum is just that ; it is nothing but space. 
Space has neither weight, dimension, nor 
boundary; it is infinity. 

Suppose the vacuum gauge shows 26 inches, 
w^hat does that mean ? It does not mean that 
there is a space of 26 inches in the condenser 
which has no air in it, or that there are 26 
inches of space in the cylinder w^hich is a vacu- 
um; it means that there is nearly an absence of 
air in the condenser, since the pressure of the 
atmosphere has forced the gauge index around 
to the 26 inch mark. Now, 26 inches repre- 
sent 13 pounds air pressure, so we might just 
as w^ell (perhaps better) mark vacuum gauges 
by pounds as by inches. The first vacuum 
gauges, however, were mercurial tubes on the 
Torricellian principle, and were marked in in- 
ches, so this system is still kept up. Suppose the 
vacuum gauge shows only 20 inches; then 
there is a partial vacuum only, for 20 inches are 
equal to 10 pounds only, and with the vacuum 
gauge at 20 inches there are foar pounds press- 
ure in the condenser, a dead loss to us, for we 



103 

are working against so much back pressure 
when there should not be any. 

Now, the best vacuum we can get with 
modern appliances and at the speed we run 
engines in these days is 26 to 27 inches, rarely 
the latter. This loss of one pound is due to the 
want of time to remove the last vestige of air 
and vapor, to the mechanical imperfections of 
our appliances, and to the fog or mist of con- 
densation, which to a greater or less extent 
pervades all condensers, whether surface or 
jet. It is creditable that we are able to do so 
much as this, but the greatest enemy engineers 
have to contend with in maintaining a vacuum 
is air leaks, pure and simple. The joints about 
a condensing engine are almost innumerable, 
and each pinhole, even, contributes its quota 
of mischief. Leaks occur through bolt holes, 
through gaskets, through castings themselves. 
The chaplets used in foundries to support cores 
are very liable to be leaky. Look out for them, 
and daub them over thickly with red lead paint. 
Paint every part of the injection pipes thickly; 
keep all stuffing boxes of injection valves well 
packed and use every means you can think of 
to guard against loss of atmospheric pressure 
by leakage of air into the condenser. Go round 
to every joint you can reach with a lamp and 
hold the flame against it. If there are air leaks you 



104 

can sometimes hear them, but when too small 
to be heard they can be seen, for the flame 
will be forced in toward the leak. Keep the 
foot valves in perfect order, and the air-pump 
bucket as well, both must be as near air tight 
as possible. Remember the adage : '^Nature 
abhors a vacuum' and will fill it in an incredibly- 
short time if she is not prevented. 

If, when the engine is working well other- 
wise, the vacuum begins to fall, so to call it, 
give more injection water. Sometimes steam 
from the boiler is hotter than at others, the 
water in the boiler falls and the steam is super- 
heated ; that calls for more injection. If the 
vacuum is still poor try the condenser by hand 
and if it is warm and getting warmer, and no 
amount of injection water w?U keep cool, see 
if the foot-valves seat properly. If they are 
cocked ever so little the water of condensation 
can not get out, and by lying in the bottom of 
the condenser kills the vacuum with its vapor. 
The injection pipes may also be stopped. In 
fresh water, eels often get drawn into the pipes 
and stop them, when the water is drawn from 
ponds ; in rivers and streams, weeds, and also 
fish, get drawn across the strainer and prevent 
the water from entering. Every injection pipe, 
whether on sea or on shore, should have a 
steam pipe let into it for use in emergencies, 



I05 
with a nozzle pointing toward the source of 
supply. It may save a long stop for cleaning 
the water pipe. 

A good vacuum is worth 13 pounds of steam 
in the boiler, and the feed water is heated to 
] 20 degrees without charge for the same. All 
it costs is the extra machinery needed to obtain 
it, an air pump, injection valve, and pipes and 
details. This once paid for is a small expense 
to maintain, so that for a term of years the 
outlay for a condensing engine is soon made 
up in the decreased cost per horse power per 
hour. That condensing engines are not more 
frequently employed is due to the belief on the 
part of the steam users that they are complicat- 
ed, costly to maintain and hard to manage. 
The exact reverse of this statement is the cor- 
rect onCn 

Pumps. 

The popular idea is that a pump has some- 
thing to do with raising water or oil, or mo- 
lasses, or any other fluid it may happen to De 
at work upon, but this is a gross error, first 
pointed out in the pages of The Engineer. 
By reason of this view, persons who run pumps 
are very often troubled about the water which 
comes to the pump, and, in case of failure of 
the pump to act, they examine into the con- 
dition or connections to the water, as if these 



io6 

had something to do with the difficulty. The 
only thing which can prevent a pump from 
working is air, and air leaks on the suction 
side and force side, so-called. Actually there 
is no suction side, neither is there any sucji 
force exerted as suction. It is a term invented 
and applied long before we knew what atmos- 
pheric pressure was, or recognized its great in- 
fluence in the work of a steam engine. The 
sole office and function of a lifting pump — so- 
called — IS to remove the air from the pipe 
which conveys the water to the pump. When 
this is done water flows to the pump by the 
pressure of the atmosphere outside upon it, 
forcing it up to the pump chambers. If the air 
is completely exhausted the water enters freely 
and the pump is said to work well. If it is 
only partly exhausted the water flows slug- 
gishly, and the pump works badly. If we need 
proof that a pump has no direct effect on the 
water itself, we can attach one to a pipe 36 feet 
long. The water will then rise in the pipe for 
32 feet, but after this occurs we may work the 
pump for all time and not get a particle of water 
through it. The reason of this is that the at- 
mosphere will not support a column of water 
over 32 feet in height, and therefore the pump 
has no effect upon it. 



CHAPTER XVI. 
Supporting a Water Column by the Atmosphere. 
Now there are many who do not understand 
clearly what is meant by the atmosphere sup- 
porting a column of water. They see a pipe 




Fig. 23 
full of water — a stand-pipe, for instance — which 
is merely a long tank upon end; or they see a 
tank at a railway station, and understand that 
these are not supported by the atmosphere, but 
^re merely reservoirs which have been filled 



io8 

up. Where, then, is the difference? The dia- 
gram appended will make this plain. This is 
aU pipe, 34 feet long from its base at^ to its 
top B. Now, suppose we fill this pipe up to 
the mark C, or any other mark eqaal to half 
the capacity of the pipe, and attach a pump at 
B, keeping it air-tight. When we exhaust the 
air from the arm D the pressure of the atmos- 
phere in the arm jFwill drive the water up in 
D say 33 feet, if there is a perfect vacuum, and 
the water will stand there just so long as the 
vacuum is maintained, no longer, unless there 
is a valve at the bottom to prevent its return. 

If the pump is stopped the water will fall 
to its level again, because air gets in through 
the pump and restores the balance. If there 
was no vacuum the water would stand at the 
same height in both arms, because there is 
just as much atmospheric pressure on one 
side of it as on the other side, and water be- 
ing heavier than air, finds its level. This is 
all the mystery there is in the operation of 
a pump of any kind whatever, and aside 
from the mechanism which drives it if a well 
pump will not perform as it should, the reason 
can be generally found on the suction side so- 
called ; the plunger or bucket does not remove 
the air so that the water can get in. It is easy 
to see, then, that a pump demands the very 



109 

best workmanship in all its interior working 
parts. The barrel should be smooth and true 
if i, bucket works in it, and the packing of the 
same should be tight. If it is a plunger-pump, 
where the plunger is clear of the barrel, the 
stuffing box should be long, well packed, and 
the plunger itself should be true and work true 
in its path. Suspect every joint on the suction 
side of leaking, and if there are screw bolts 
which go through castings on the suction side 
suspect them also ; a good deal of air can get 
in through a very small opening. If there are 
many of these the net result detracts from the 
work of the pump. Friction of water is an- 
other element against a pump. This in the ag- 
gregate is very great in long pipes and in tor- 
tuous passages. Elbows and rough castings 
can take off much from the efficiency of a pump 
where the water has to be forced to it for long 
distances by the atmosphere, and this must be 
considered in the erection of any plant. There 
are only 14.7 pounds pressure on ihe water 
outside to get it where we want it, and this 
only when we have a perfect vacuum in the 
pipes ; with an imperfect one we have much 
less pressure. All this relates to what is known 
as the suction side of a pump, but, on the forc- 
ing side it is just as bad if the pipes run in- 
directly. All feed pipes should go as straight 



no 

as they can be run to the boiler, but sometimes 
it is not possible to do this, and loops and ver- 
tical bends are made in them. Air collects in 
the tops of these bends and stops the water 
quite as effectually as a block of wood could. 
It lies on top of the water as wood floats on it, 
because it is very much lighter, and is com- 
pressed so much by the action of the plunger 
that it resists the main flow of the current, and 
the water surges back and forth in the cham- 
bers. This is fully shown in an air chamber, 
which is a well known adjunct to pumps, both 
single and double-acting. If metal valves are 
used for the lift or force sides, they should be 
carefully examined, from time to time, to see 
that they are tight on their seats, and lift 
squarely, and seat fairly. An unsuspected 
source of trouble is often found in the seats of 
valves. These last are brass bushes driven into 
cast-iron chambers. Sometimes these cham- 
bers are bored out for the valve seats, and very 
often they are not, but taken as they come from 
the foundry. In work of this character it is not 
uncommon to find leaks. The seats also work 
loose in the castings, and leak from that cause. 
Another difficulty with pumps is found in the 
lift or rise given the valves. Quick working 
pumps require very little lift to the valves on 
either side, but the most should be given on 



Ill 

the force side. Divide the diameter of the 
valve by four; this will give a lift equal to the 
area of the opening in the valve seat, which is 
all that can be delivered to the pump barrel. 
A two inch valve, then, should lift only half 
an inch, and even this will be found too much 
in some cases. Plunger pumps that run at high 
speed, or over lOO feet per minute, are very apt 
to pound violently and make a great deal of 
noise. This can be overcome wholly by sim- 
ply coning the end of the plunger to an angle 
of 30 or 40 degrees. Pat the plunger in a lathe 
and bevel the end off, and there will be no more 
pounding. The reason for this is not easy to 
find. Pumps are still used in many places for 
feeding boilers, but in a majority of cases in- 
jectors are used. These last are simply man- 
aged, and the fullest directions are sent with 
them by the manufacturer. If they are follow- 
ed implicitly there will be no trouble, but if 
persons undertake experiments on their own 
account ihey must not blame the apparatus. 

These are succinctly the principles govern- 
ing the action of condensing engines and the 
pumps by which they are worked. All pumps 
act upon the same principles as those previ- 
ously alluded to. Whether the detail which ex- 
hausts the air from the water supply pipes is a 
scroll, a screw, or a fan attached to a shaft and 



112 



rotated by it, as in a centrifugal pump, whether 
it is a simple bucket or a plunger, the fact is the 
same: the air must first be removed before any 
water can get to the pump, and the special de- 
tail, the fan aforesaid, or the bucket or plunger 
which forces the water out of the pump cham- 
ber has no direct influence upon drawing the 
water itself. Jt may be that we have reiterated 
this too often, but we think not, in view of the 
fact that we were told quite recently by a per- 
son in charge of a pump that the suction 
valves were so heavy that the plunger could not 
Hft them. It is very hard to get rid of notions 
and ideas; the more erroneous they are the 
more difficult it is to abandon them. This is 
our apology, if any is needed, for insisting 
upon the facts laid down as regards the 
action of pumps. Also, let us say here, that in 
previous chapters we have stated that water 
v/ould rise only 32 feet in a pipe in a perfect 
vacuum. We should have said in a working 
vacuum, which is far from being a perfect one. 
The mean pressure of the atmosphere within 
its known limits is 14. 7 pounds per square inch, 
which corresponds to a column of mercury 
(supports it) 29.9 inches high, or will support a 
water column 33.9 feet high at the sea level. 
These are the exact figures, but we have all 
along in this work preferred to deal with every 



113 

day results and figures, rather than submit mere 
cut and dried recitals of tabulated details. 

Dismissing the steam engine and its belong- 
ings, with the bare review of its functions and 
management which has been possible in the 
assigned limits of this work, and assuming that 
we have a new plant to start for the first time, 
let us mention some details that are of great im- 
portance. 




CHAPTER XVII. 

Starting a New Plant. 

New engines and boilers should be started 
with great care; this statement applies particu- 
larly to the boiler. If the latter is large, the 
fire under it should be started at least three 
days before the boiler is actually needed for 
work, and the fire should be very small indeed 
at first. For the first day no attempt should be 
made to raise steam, and the fire should not be 
urged in the least. The water should be al- 
lowed to get ''hand- warm'* only, and be kept 
at this temperature for twenty-four hours. The 
reasons for this must be apparent with very 
little thought. Everything is cold on the start, 
and all the dimensions will be greatly changed 
by heat, and unless great care is taken at the 
outset much injury can be done to the brick 
work setting and the boiler itself. 

For the second day the temperature may be 
increased to nearly the boiling point, but the 
fire should not be driven. The furnace doors 
must be kept shut all the time, and the ash-pit 
doors also, the amount of draught and of fuel 
being governed so as to keep the boiler from 
making steam. On the third day the boiler 
may be allowed to make steam, but the pres- 
sure must be brought up gradually, and the fire 



115 

upon no account forced. The furnace doors 
must be always kept closed as before. As the 
pressure rises above the atmosphere, open all 
the steam connections and allow the steam to 
warm the pipes thoroughly before putting 
greater pressure upon them. Do not close any 
valve with a rush when the pressure rises to the 
working point. 

The boiler should be full of water on the 
start, three full gauges, so that while the pres- 
sure is still low the boiler can be blown down 
— through the blow-cock — to get rid of all the 
rubbish that has accumulated in inaccessible 
corners. Open the blow-cock steadily, not 
w^ith a twitch of the handle, and bl ^\v down to 
two gauges. This should not be done until a 
few minutes before starting the engine; the teed 
will not be needed for a few minutes then, and 
in that time all the feed-pipe connections wull 
warm up and expand equally. 

Try all movable joints, handles, cocks, safety 
valves, everything in short, to see if they work 
properly, and examine every valve and stuffing 
box personally to see if they have been packed 
properly. Look carefully to all the joints un- 
der pressure, and do all this before a working 
pressure is raised; keep up this inspection from 
time to time as the pressure increases. On 
starting the engine, open all the cylinder cocks 



ii6 

to blow out the condensed water which has 
accumulated in the pipes and cylinder. This 
is imperative, not only to get rid of the con- 
densed water, but to blow out the sand, chips 
and minute filings, that can be removed in no 
other way. These have accumulated in the 
engine while it was being built and erected, 
and in no other way can they be so effectually 
removed. Move the hve steam valves, so that 
steam is blown through both ends of the cylin- 
der for the purpose mentioned. 

Before turning the engine over the center for 
the first time make absolutely sure that every- 
thing is clear ; give the engine steam easily, 
and run the crank over on the three-quarter 
position; then give steam the other way, if 
there is hand gear which admits of it, and drive 
the crank back again. Do this carefully, and 
before the engine is finally allowed to pass the 
center shut the throttle entirely, so that if any- 
thing is wrong or anything carries away, the 
mischief will be confined to one stroke. The 
flywheel will carry the engine over the center. 

An engine should be started the first time 
under very moderate pressure ; five pounds 
should be enough if the engine is properly 
made. No power is needed, and the only 
points to be established are, whether every- 
thing is in apparent good working order. 



117 

If possible, do not lace any main belts 
until after the engine has been tested. There 
is no knowing- what may have to be done, 
for mistakes are possible to all until the en- 
gine has been tried. If indicator attachments 
are on, take friction diagrams at this time 
with the unloaded engine, and see what it 
requires to move itself. Do the same when 
the main belts and shafting are on. without 
the machines, and valuable data will be had 
for future reference. As to the engine con- 
nections, the main bearings, crank-pin, and 
cross-head end, should be left perfectly easy. 
If they thump slightly, it does not matter when 
the engine is running slowly. Thumping 
from loose connections is very different in 
sound from pounding for want of proper ad- 
justment, and the careful and experienced 
engineer will detect the difference at once. 

In all that has been said, we hive endeavor- 
ed to inculcate the idea that, above all other 
things, the most watchful care and supervision 
is needed on first starling a new engine and 
boiler. On such occasions a tremendous 
change is introduced. Cold metal is made hot, 
and, in this transition alone, inconceivable 
force is generated. It is none the less power- 
ful because it is invisible, and makes itself 
known only by rupture. Boilers are made 



ii8 

leaky by careless handlin^^ on the start which 
were perfectly tight and well made, and strains 
are set up within them by forcing^ them, which 
materially affects their life. The same is true 
of the brick-work, if the boiler is so set, and it 
is for this latter, primarily, that we advised 
three days moderate heating of the boiler upon 
starting it. It takes, or should take, a long 
time to heat a brick wall alike — so that it all 
goes together, and three days is none too long. 
If these directions are followed, properly 
built engines and boilers will perform well 
from the start. There will be no running back 
and forth to the shop, or calking leaks, re- 
making joints, or any sort of fuss. There will 
be that harmonious straight-away condition of 
affairs which mark the difference betv/een a 
man who knows his business and one who does 
not. 

From what has been said in preceding pages 
it is apparent that to be a successful engineer 
requires care and skill of the highest quality. 
The attention necessary to keep a steam plant 
up to its best condition all the while must be 
unremitting, otherwise great loss results. It 
does not follow from this that an engineer 
should be hopping around from engine room 
to fire room, or running here and there with a 
squirt can, or in a fuss generally ; what we 



119 

mean to inculcate is that an engineer should 
keep the run of his plant in his head at all 
times, and not suppose things are all right 
because no accident has happened. Accidents 
never happen to careful men ; they only happen 
to persons who suppose instead of knowing, 
as far as human foresight can go. Mysterious 
boiler explosions, mysterious flywheel burst- 
ing, mysterious anythings about steam engines, 
could, if all the facts were known and the 
naked truth were told, be traced to a condition 
of things previously known to some one which 
was willfully neglected, *'Let well enough 
alone," is a good maxim in an engine room, 
but this does not mean that bearings are never 
to be examined, boilers never cleaned, or never 
examined for defective braces, and the whole 
routine of an engineer's duties neglected. For 
ten hours daily, at the least, an engineer must 
keep watch of his engine and boiler, for things 
go wrong when they are least expected to. In 
a factory where hundreds of people are em- 
ployed, a very small matter to an engineer may 
precipitate a panic which will cost many lives, 
and it is for him to see that it does not occur 
through his carelessness. We were in an en- 
gine room — fire room, rather — once when a 
rivet blew out above the water line, and made 
a great fuss. A youth who was in the place 



I20 

started for the door, shouting that the boiler 
had burst, but he did not get far enough to 
frighten others before he was caught by the 
collar and a little advice given him that was of 
service. When a rivet blows out it is a simple 
matter to whittle a pine plug and jam it in the 
hole, either above or below the water line, and 
it is not a bad idea to have plugs handy for this 
purpose. It is not uncommon for rivets to 
blow out. 

Another point that an engineer should bear 
in mind is that the engine is upon no account 
to be stopped in working hours, unless it goes 
to pieces, direct orders are given, or danger to 
life and limb is imminent. No engineer should 
stop a factory engine where goods are turned 
out by the piece, or by the yard, or any other 
quantity, for a hot bearing, or because some 
detail of the engine will be ruined if kept run- 
ning:. The cost of most details of an engine is 
slight, but if the detail costs a hundred dollars 
it is better to lose it than a thousand dollars' 
worth of work, or two hundred dollars' worth 
of time. This is particularly the case in places 
where power is sold to tenants. Every revolution 
of the engine means some fractional part of a 
dollar to them, and the stopping of an engine 
for some trifling, or possibly serious, expense 
to the landlord, might mean ruin to a tenant, 



121 

who would, perhaps, depend upon that very 
half hour to complete a contract in a given 
time. Upon trifles, as we call them, very great 
events depend sometimes. 

We repeat again, never stop an engine in 
working hours except for the direst necessity. 
Also, never start an engine after it has been 
stopped without a direct written message, or 
direct personal notice, from the man in charge. 
Suppose nothing. It is a serious business to 
neglect either of the precautions above men- 
tioned. 






CHAPTER XVIII. 

Water-Tube Boilers. 
Now that water-tube boilers are supplanting 
fire-tube boilers, both for stationary and marine 
work, it is important that an engineer should 
know some of their chief features, and the rea- 
sons why they are driving out fire-tube boilers. 
These are, broadly, their immunity from dis- 
astrous explosions (there being no shell and 
but a limited quantity of water in them), their 
economy of maintenance, both in running and 
in upkeep, their accessibility for cleaning and 
their high efficiency as evaporators. 

Boiler Explosions. 

It is not asserted that no water-tube boiler 
has ever been ruptured as to its tubes, but it is 
asserted that no explosions like those of shell 
boilers — that is, fire-tube boilers — can be 
traced to w^ater-tube boilers. The reason is, 
for one thing, that there is no shell of large 
diameter on water-tube boilers, and, for 
another, that the rupture of a tube acts like a 
safety valve — in a certain sense, and releases 
but a small quantity of water compared to the 
total water content of the boiler and compared 
to the water content of fire-tube boilers. 



123 

The idea that when a steam boiler is full of 
water it is in no danger of explosion is an ab- 
surd one and no longer entertained by intelli- 
gent engineers. The more water there is in a 
boiler which is in a condition to explode the 
greater the danger, for it is the large body of 
heated w^ater giving up its stored energy of 
hundreds of tons which causes the terrible de- 
struction when a fire-tube boiler explodes. 
The moment of explosion of a boiler's shell is 
small and its duration short when above the 
w^ater line, but if the rupture occurs below the 
water line then the total energy of the heated 
water is directed to the injured part and de- 
struction of the whole plant follows. 

It is very similar to the ignition of a given 
quantity of gunpow^der unconfined and a simi- 
lar quantity enclosed in a tube. The so-called 
'* mysterious " boiler explosion, w^hich is often 
reported in the daily papers, is not mysterious 
to some one who was about it or in charge of 
it at the time and who knew of its condition, 
but refused to repair it. 

Economy of Maintenance. 

The water-tube boiler, as compared with the 
fire-tube boiler, is far more economical in its 



124 

freedom from costly repairs. The chief parts 
which require renewal in a water-tube boiler 
are the tubes nearest the fire, but with proper 
management they will last about ten years. 
When they do require to be renewed the ex- 
pense is very small indeed per horse powder of 
the engine driven, and the time required, w^hich 
is also part of the cost, is scarcely worth men- 
tioning. Water-tube boilers are in action to- 
day which have not cost one cent for repairs of 
any kind whatsoever after many years' use. 
The New York Steam Company has 14,000 
horse power Babcock & Wilcox Company 
Water-Tube Boilers running night and day for 
several years, the cost of repairs has been three- 
quarters of one cent annually per horse power. 
Other boilers of the same type have been in 
constant use day and night without costing one 
cent for repairs, so it is easy to see that, as 
compared with fire-tube boilers, the water-tube 
is the cheapest to run. 

Evaporative Efficiency. 

Steam boilers in these days are rated by their 
ability to turn water into steam, and the term 
horse power cannot be properly applied to 
them. 

Regarding the '' power " of steam boilers, 



1^5 
the word is misapplied, but it is still used by 
reason of custom, and because there is no other 
popular term to express a boiler of a given size. 
It is obvious that a steam boiler is merely a 
magazine of stored force which may be, and is, 
of varying power in accordance with the way 
in which it is used. A reservoir of water 
could not be said to be of 5,000 or any thou- 
sand horse power if its contents were directed 
on to a turbine wheel, unless it was also stated 
how long and with what volume and fall the 
water was used. Similarly, a steam boiler is 
of varying power for a given rating in grate 
and heating surface, according as its stored 
force is used. The rating of steam boilers 
is now expressed in terms of their ability to 
evaporate certain quantities of water into dry 
steam in a given time, and this is the only fair 
test that can be given. The purchaser then 
knows exactly what he is getting, and can use 
the steam in one hour or in ten hours. No 
questions enter into argument as to the amount 
of heating and grate surface ; these things rest 
with the designer of the boiler, and it stands 
or falls by its performance. These last values, 
heating and grate surface, have greater or less 
significance, according to the disposition of 
them and their relation to each other. A square 



126 

foot of heating surface in a boiler is of nuicli 
greater efficiency in one place than in another. 
To merely state, then, that a boiler has ten 
square feet of heating surface to a horse power 
means nothing at all as regards its evaporative 
effect, and its performance cannot be accurately 
relied upon. 

This will be clearer to non-technical readers 
when it is stated that a simple engine, having a 
single cylinder, should produce a horse powder 
upon 30 pounds of water evaporated into steam 
at 70 pounds gauge pressure ; a compound en- 
gine, having two cylinders and working at 
from 6 to 10 expansions, will produce a horse 
power for an expenditure of 20 pounds of 
water ; and a triple cylinder engine, working at 
16 to 30 expansions, should give one horse 
power for every 15 pounds of water evaporated 
into steam per hour, in all of the above cita- 
tions. Now, the same boiler wall supply all of 
these engines (in rotation) if the proper pres- 
sures for the work are carried, but the power 
developed is vastly greater with the high ex- 
pansion engines than with the simple engine. 
Very much higher values could be given for 
high expansion engines, but the writer has 
taken the average. It seems plain, therefore, 
that the power of a boiler begins and ends with 



127 

its ability to evaporate certain quantities of 
water in a given time. 

Furthermore, the evaporative power of boil- 
ers depends largely upon the amount of coal 
burned upon the grate in a given time, so the 
power of a boiler of certain dimensions can be 
augmented over its normal power by using 
artificial draught of one kind or another, air 
driven in directly by a fan, or air drawn in by 
induction, as with a jet, or with the exhaust 
turned into the chimney. 

Take the case of a locomotive; under the 
stimulus of the exhaust, a locomotive of say 
1,200 square feet of heating surface and 18 
square feet of grate surface will develop 600 
horse power, but the normal capacity rating of 
a locomotive boiler under stationary boiler 
rules would be only 120 horse powder. Each 
pound of coal boils ofif so much water into 
steam; with forced draught rather less per 
pound of coal than with natural draught, but 
since 75 pounds of coal are burned in the same 
time (per square foot of grate) that 15 pounds 
of coal are burned by natural draught, nearly 
four times the amount of water is boiled into 
steam in a given time. 

The fact that high powers can be obtained 
from boilers of a given heating surface is well 



128 

shown by fast yachts and by torpedo boats. A 
high speed steam yacht built last year has a 
boiler of only 1,200 square feet of heating sur- 
face, but this boiler has been worked up to over 
600 horse power with quadruple engines and 
forced draught of great intensity. As regards 
this last, the punishment that a boiler will 
stand without giving up the ghost incontinently 
is astonishing, and water-tube boilers seem 
specially adapted to this method of driving 
them. Fire-tube boilers, especially those of 
the vertical type, are the least economical and 
efficient of their class, particularly when rated 
by the square feet of heating surface they con- 
tain. The tubes of plain vertical boilers util- 
ize but from one-half to two-thirds of their 
total surface, for this portion is the only part 
reached by the water, with an exception in the 
case of submerged tubes. Suppose, for ex- 
ample, that a tube is four feet long above the 
fire box, the water would then be carried in it 
for only thirty inches of its length, the re- 
mainder being for steam room. A vertical 
tubular boiler having forty 2-inch tubes four 
feet long has a nominal heating surface in the 
tubes of 83 square feet, but owing to the de- 
fect of its type it has actually but 54 square 
feet that is of any value as steam generating 



129 

surface. This is not the case with water-tube 
boilers of any other type, for the entire tube 
surface is directly in the fire, and exposed to 
an equal temperature all over. The average 
evaporation and consequently the efficiency 
per square foot of grate and per pound of coal 
is much higher in the water-tube boiler than in 
the fire-tube. Established records of one type 
of wdiich there are larger batteries installed, 
greater aggregate horse power and longer in 
use than any other — the Babcock & Wilcox 
Company boiler — show that the evaporation 
runs from 10.94 pounds of water per pound of 
combustible to 11.84, ^^^^1 i^ o^^ ^^se reached 
the quantity of 12.42 pounds per pound of 
combustible. Even under '' actual condi- 
tions,'' by which is meant every day work, 
with coal as it came and the boiler as it was, 
clean or dirty, the evaporation averages t^n 
pounds. 

Contrast this with the average evaporation 
of the average fire-tube boiler of all types, and 
it is easy to see why the water-tube boiler gains 
in favor. 

In comparing these tw^o classes of boilers — 
fire-tube and w^ater-tube — general accessibility 
is a feature of importance, and in this respect 
the water-tube boiler surpasses the fire-tube. 



130 

Horizontal fire-tube boilers are very difficult to 
keep clean, some parts being impossible to 
reach, beneath the lower course of tubes, for 




example, but in inclined water-tube boilers the 
tubes can be opened from end to end. 

Many Kinds of Water-Tube Boilers. 
Broadly, all boilers which have the fire out- 
side of the tube and the water inside of it are 



131 

water-tube boilers, but there are very many 
kinds of them; that is, the arrangement and 
disposition of the heating surfaces varies 
greatly ; also the proportions of grate to heat- 
ing surface and heating surface for a given 
evaporation, but it is proper to say that there 
are more inclined tube water-tube boilers in 
use than any other. They are fast supersed- 
ing fire-tube boilers in electric-lighting sta- 
tions, electric railways, water works, and sugar 
houses. The oldest and best known of this 
type is the Babcock & Wilcox boiler, and it is 
shown in Fig. 24. 

The horizontal tube water-tube boiler is 
here represented by the Roberts Safety Water- 
Tube Boiler, Fig. 25, and it is also the oldest 
and best known of its type. 

In this type of boiler the water is delivered 
by the pump into two feed heating coils, one 
on each side of the drum, which abstract a 
good deal of heat from the gases that would 
otherwise pass up the smoke-stack. From these 
coils the water passes into the drum. This 
heated water is then taken into the circulation 
and carried down through the '' downflows '' 
— the two large pipes on each side shown in 
the front of the cut — the same number being 
at the back end. From the '' downflows '' the 



132 

water passes into the side pipes, one on each 
side of the grate bars, and up through the up- 
flow coils and into the drum. The upflow 
coils are directly over and form the crown of 
the furnace. The steam rises to the top of the 
drum and the water not generated into steam. 




Fig. 25.- -Roberts Safety Water-Tube Boiler. 

but carried up by the steam, is sent down the 
'' downflows '' again by the circulation. The 
steam then passes through a spray pipe in the 
drum and out into two superheating coils — 
one of which can be seen above the fire-brick 
on the side of the cut. The superheated steam 
supply is taken from the terminals of these 
coils. 



^33 




Fig. 86.— Watson Radial Water-Tube Boiler. 



134 

The sub-vertical tube type of water-tube 
boiler is well represented by the Watson Radial 
Water-Tube Boiler, Figs. 26 and 2J. 

This boiler is constructed wholly of steel 
plate and steel tubes, and is, therefore, free 
from strains caused by metals with variable 
ratios of expansion. In its present form any 
tube which may wear out by corrosion or use 
can be withdrawn readily in a short time, there 
being but one bolted joint, and that a small one, 
to break. 

Construction: The tube system is in the 
form of a cone, inclined over a central furnace, 
the gases and heat from which are diverted 
between the tubes by a bafifle-plate in the upper 
part directly under the smoke-tube. The tubes 
are fastened in the tube-sheets by expanding 
them in the lower sheet and expanding them 
in the upper tube-sheet. The tube-sheets are 
inclined, as wall be seen in the sectional en- 
graving, so that the tubes are at right angles 
with them. 

It w^ill be seen by inspecting the sectional en- 
graving that the tubes are very widely spaced 
at the bottom, and converge at the top; this 
greatly facilitates the circulation of the gases 
and also breaks them up so that combustion of 
them is assured. The ash-pit doors are close 



135 




Fig. 27.-5 H. P. Watson Launch Boiler. 



Height over dome, 3 ft. 8 in.; weight, 400 lbs = 
With exhaust in Stack will develop 7 II. P. 



136 

to the ground and can be opened or closed by 
the foot; fires are easily cleaned and cinders 
raked out, as all engineers can see. 

Circulation: A feature of the Watson Radial 
Water-Tube Boiler is its perfect, natural cir- 
culation from the moment a fire is started. 
This is attained by the following means : A 
solid air-tight sheet-steel diaphragm extends 
from bottom to top between the outside row 
of steam tubes and the circulating tubes, broken 
as to continuity by the fire door only. Outside 
of this diaphragm are the circulating tubes. 
The action is as follows : So soon as heat 
strikes the inner row of tubes the water in 
them is driven up, and in obedience to a natural 
law, flows outwardly toward cooler water. A 
pot on the fire always boils in the centre first, 
and in like manner the water in this boiler 
follows the same law. As it rises in the inner 
row of tubes it falls in the outer (or circulating 
tubes) and the cold water is constantly dis- 
placed by heated water. This causes the water 
to circulate rapidly and the boiler gets hot all 
over simultaneously. The advantage of this 
is too obvious to need further comment, and 
accounts for the rapid steaming of the boiler. 

The bent-tube type of water-tube boiler is 
shown in the engraving, Fig. 28, which 



^Z7 







bo 



138 

gives two views of the *' Daring " type of 
the Thornycroft boiler. The Thornycroft 
" Launch '' boiler, Fig. 29, is good for light 




Fig. 29. —Thornycroft Water-Tube Boiler, *' Launch " Type. 

river work. It is provided with water fire bars, 
which are kept so much cooler than ordinary 
bars by the strong current of water rushing 
through them that clinkers do not adhere, and 
a great deal of the trouble usual in firing small 
boilers is eliminated. Their weight is, of 
course, exceedingly low. 



139 

Fig. 30 shows a side view of Babcock & 
Wilcox wrought steel construction marine 
boiler for 200 pounds pressure. All the pres- 
sure parts of the boiler are of wrought steel. 




Fig. 30.— Babcock & Wilcox Marine Boiler. 



Before passing from marine boilers, men- 
tion must be made of the well-known Bellville 
type of water-tube boilers. This boiler has 



140 

1)een installed on some of the fastest cruisers 
afloat. See Fig. 31. 

All of these boilers have peculiar features of 
their own and have different proportions, but 
it is not possible to give details of their con- 
struction, neither would it be proper in a work 
of this kind to express a preference for one 
type over the other. They are employed both 
in stationary and marine work, and, as may be 
seen from their details, are rapid steamers. 
With some of these boilers for marine work 
it is possible to generate 150 pounds of steam 
by natural draught from water at 35 degrees 
F. in twenty to thirty minutes, and all of them 
are constructed to stand 250 pounds of steam 
and upward. In order to pass Government in- 
spection they must be tested to double that 
pressure, and it is easily seen from this fact 
that such boilers have great strength ; all the 
materials are of steel and all the holes are 
drilled, and no plate under 60,000 pounds ten- 
sile strength is allowed to be used in their con- 
struction. 

Why Water-Tube Boilers Steam Rapidly. 

By looking at the engravings it will be seen 
that the water in these boilers is contained in 
tubes of small diameter directlv in the fire, or 



HI 

in direct communication with exceedingly 
high temperatures. 

A tube of I -in. outside diameter and 30 in. 
long contains half a pint of water ; the super- 
ficial area exposed to heat of such a tube is 
94i square inches, or about the area of an 8 in. 
by 12 in. pane of glass. Now, half a pint of 
water on this surface is a thin film, and when 
exposed to the heat of a very hot fire, say 
2,000 degrees F., is evaporated instantly, as 
one may say. By the plan of the boiler this 
w^ater is in continual circulation, sweeping over 
all the highly heated surfaces, so that, virtually, 
the water constantly goes in at one side, or one 
end, as the case may be, continuously issuing 
at the other end as dry steam. All boilers are 
not fitted with i-in. tubes ; some types have 
much larger tubes, but their superficial area is 
correspondingly greater as well. Compare 
this action with the fire-tube boiler, where the 
w^ater is anywhere from 3-in. to 6-in. deep on 
the tubes, and we have the explanation why the 
water-tube boilers are the most efficient, by 
which term is meant that the heat generated 
by the fuel burned is applied directly to the 
heating surfaces, which are, again, directly in 
the zone of the fire and close to it, so that the 
products of combustion have but short distances 



14^ 



rttV OUTLET 

rROM EC0N0MI6ER LJ _ 



STEAM 
OUTLET 



CEED INtrr TO BOtLER rf^ 
AFTER LEAVING -^ g 
ECONOMISER 




143 
to travel to reach their work. This cannot be 
said of fire-tube boilers set in masonry. 

Torpedo-Boat Boilers. 

From the facts just cited as regards water- 
tube boilers it is possible to get very high 
evaporation (boiler power, so called) from a 
very small and very Hght apparatus, and it is 
this quality which makes them particularly 
suited for torpedo boats and vessels akin to 
them (high speed yachts). As a rule it ruay 
be said that these boilers are less than half the 
weight of fire-tube shell boilers and far more 
compact. They have a very low center of 
gravity and for very considerable powers can 
be put under deck in a light draught vessel. 
The heating and grate surfaces allotted to the 
water-tube boiler are much less than the fire- 
tube boiler per horse power evaporation. This 
last quantity varies from 30 pounds of water 
for a common slide valve engine to 20 pounds 
of water for a tw^o-cylinder compound engine, 
and to 15 pounds for a three-cyHnder or triple 
expansion engine. It has been found in prac- 
tice that five square feet of live heating sur- 
face per one horse power evaporation is ample 
for boilers of this type, and many of them 
show a horse power evaporation upon three 



144 

square feet of live heating surface ; the grate 
surface runs from one square foot of grate to 
twenty-five square feet of heating surface, to 
thirty-five, forty, and as high as fifty square 
feet of heating surface to one square foot of 
grate surface. Compare this with the allot- 
ment in fire-tube boilers for the same purpose, 
ten and twelve square feet of heating surface 
per horse power evaporation, and additional 
evidence is given of their relative efficiencies. 

Mention has been made in previous lines of 
the high powers exerted by water-tube boilers 
of the torpedo boat type, and these are cer- 
tainly phenomenal. It seems quite impossible 
to persons familiar with heavy, slow combus- 
tion, shell boilers that boilers of five and six 
thousand power can be put into a small vessel 
of say 130 feet length by ten feet beam, or 
width ; far less superficial area than is contained 
in an ordinary city lot, for this last has 2,500 
square feet area w^hile the torpedo boat has 
little over half of it. 

It will aid to a full comprehension of the 
apparent paradox when we consider the type 
of engine used and the steam pressures carried. 
The engines are in all cases high expansion 
engines — triple or quadruple stage — and run at 
high piston speed, i.ooo and 1,200 feet per 



HS 
minute being not uncommon. Now the boilers of 
these torpedo boats are only directly concerned 
with the high pressure or first cylinder of the 
system, because it exhausts into all the others 
in turn, and if it can supply the first cylinder, 
at say 250 pounds gauge pressure, the boiler 
gets credit, so to speak, for the power exerted 
by the other three cylinders. If, therefore, the 
boiler can manage the high pressure cylinder 
developing one thousand horse power per hour, 
it is furnishing steam (under the conditions) 
practically for three thousand horse power. 

Again, take the case of a locomotive engine 
in common use. An average modern express 
engine has about 1,800 square feet heating 
surface ; at the rating usually followed in sta- 
tionary practice this would only give 180 horse 
power for the boiler under natural draught, but 
with the stimulus of the exhaust in the chim- 
ney a locomotive boiler wnll develop a horse 
power for less than two square feet of heating . 
surface and supply two cylinders 20-in. by 24- 
in. at 300 revolutions per minute, when under 
natural draught it would not supply one at 150 
revolutions per minute. Examine the grate 
surface of the express locomotive boiler and it 
will be found to have 30 square feet, a ratio of 
heating surface to grate surface of 60 to i, or 



146 

about half of what a stationary boiler would 
require for the same work. It follows, there- 
fore, that high powered boilers of small size 
obtain their efficiency from their ability to gen- 
erate large quantities of steam rapidly at very 
high pressures when under forced draught, the 
conditions being entirely dissimilar from those 
of stationary boilers. 

Management of Water-Tube Boilers. 

Under ordinary circumstances — that is wath 
natural draught and slow combustion, the man- 
agement of water-tube boilers is the same as 
that of any boiler, but since the tubes are small 
(and these control the amount of water ex- 
posed to the fire) it is necessary that they 
should be kept absolutely clean. This is par- 
ticularly the case with the lower course of 
tubes, or those nearest the fire. These take 
the most intense heat and scale must be care- 
fully guarded against. If the water is at all 
bad, or hard"^ it is essential to give strict at- 
tention to this detail, for unless these tubes are 
kept free trouble of a serious nature is certain 
to occur. It is very easy to say that every one 
knows this, and it is therefore superfluous to 
mention it, but it does not always follow that 
what every one knows every one attends to. 

* See Collett on Water Softening. (Spon & Chamberlain.) 



147 

The old saying that '' want of care does more 
harm than want of knowledge '' is particularly 
applicable to all boilers, and to sum the whole 
case in a very few words, the careful man 
about a steam boiler is the one who never has 
any trouble. Every man in charge of a steam 
boiler is supposed to have sense enough to see 
that he always has water at the proper level be- 
fore putting fire under it, but there is a great 
deal of laxity in this matter of firing."^ 

Not so much is said in the public prints 
about the smoke nuisance as there was a few 
years ago, and there is no question but that the 
agitation of this matter of smoky chimneys in 
large cities was a very good thing for steam 
users, for if it did nothing else, it caused fire- 
men to attend more carefully to their work. 
Smoke prevention starts directly from the fur- 
nace door, that is to say, the fireman practi- 
cally prevents it by not making it, but he has 
to do a good deal more work than in the days 
when he threw in all the furnace would hold 
and then took a rest for half an hour with a 
smoke pipe of his own in his mouth. Practice 
proves that the smokiest coal can be deprived 
of its terrors by judicious firing, " the little 
and often " theory ; but it is harder on the man 

* See Dahlstrom ; The Fireman's Guide. (Spon & Cham- 
•berlain.) 



behind the shovel. The writer has fired bi- 
tuminous coal — a scoopful at a time — without 
producing smoke of any moment at all, but it 
is not a pastime to do it, and it must not be 
wondered at that mere flesh and blood rebels 
against '' crooking the pregnant hinges of the 
knee '' hour after hour at such work. It is 
also the most economical method of firing, and 
those who have been used to heavy firing are 
advised to try light as an improvement. 

Firing a steam boiler, however, has to be 
done differently with every plant, or more 
properly, all plants cannot be fired in the same 
way, nor all grates in the same manner, but 
each one has its peculiarities which those in 
charge must discover. Cleanliness in boilers — 
inside and out — is as important as anything 
else about them ; soot is a non-conductor, and 
it is not to be expected that a boiler will steam 
freely if the heating surfaces are covered 
with it. 

If boilers do not steam freely when they 
have never given any trouble previously the 
cause may be found in a combination of several 
things. Sometimes the atmosphere itself is so 
'' heavy " as it is called that the fuel will not 
burn or the gases combine with it, but it is 
more frequently the fault of dirty fires when 



149 

steam is short than a heavy atmosphere. The 
ash pit, should be always bright, and one can 
tell at a glance whether the fire is doing its 
duty or not. 

'' Perfect combustion,'' so often claimed for 
this or that appliance, or smoke preventer, is 
impossible under the conditions prevailing in 
commercial steam making, because different 
volumes of air are required at every stage of 
the process. It is important to distinguish be- 
tween weight and volume in combustion, A 
given weight may enter through a one-inch 
hole if it has velocity enough, but volume is re- 
quired in order that the air and gases may be 
thoroughly mixed, but while we cannot hope 
for perfect combustion we can obtain fairly 
good combustion by careful attention to the 
fires. 



CHAPTER XIX. 
The Highest Qualities Demanded. 

Finally, let me say, in conclusion of this 
work, that the duties of an engineer worthy of 
the name call for the highest qualities, and are 
not to be lightly undertaken, or held in low es- 
teem. A man v/ho stops and starts an engine 
is not an engineer, and has no pride in his 
business, because he knows nothing of it ; he 
does not wish to know any more than that 
opening the throttle lets steam into the chest. 

But we should not be discouraged or care- 
less ourselves because such men get places, to 
the exclusion of their betters. There are 
usurpers everywhere. Quack doctors abound, 
so do quack ministers and shyster lawyers. It 
would be quite as logical and sensible for 
skilled professional men of these classes to give 
up trying to rise as it would be for an engineer 
to follow the same course. Knowledge of our 
business is paid for always, but an. engineer 
must know where to find the best market for 
his services, exactly as every other man must 
who has something to sell. A dentist, let us 
say, settles in a certain locality and does not 
thrive. He does not immediately accuse his 
profession as the cause of his trouble, but he 
says that there is no business in that place, and 



searches until he finds one that is better. 
"Knowledge is power" is as true to-day as 
ever, but there are some places that are better 
than others to sell it in. 

If an engineer spares no effort to improve 
himself, and studies first principles so as to 
know where to look for the cause and cure of 
troubles never encountered before, he is a bet- 
ter man for a steam user than a mere stopper 
and starter who does not wish to learn. Some- 
where there is a steam user looking* for him, 
and it is the engineer's business to find a place 
where he is paid for his work. We need only 
look around us to see engineers who have 
good homes, are socially esteemed, and are 
brin^fing up families to be a credit to them- 
selves and the State. These men started from 
small beginnings, and were careful, prudent 
and anxious to learn. They did learn, and 
that is why they thrived. 

The Man Himself is the Factor. 

It IS not the business which a man follows 
that keeps him down or lifts him up ; it is the 
man himself in every case, and it is well to 
bear in mind that a man can not be an engi- 
neer, or a lawyer, or a doctor, or anything else, 
at abound. Long service, patient waiting, dis- 
appointments, reverses, learning through them 
and learning by success also — all these have 



S'- 



their perfect work. No faithful service is ever lost. 
If a steam plant is in perfect order and runnings 
lower than others in the vicinity be assured 
that if the employer does not see it, others do, 
and perhaps when we least expect it we may 
get a call to go elsewhere with manifest benefit. 
There are many things conducive to success 
in eng^ineering, as in all other callings which 
mankind follow, and none of these has more 
effect ill business intercourse than a pleasant 
address. Engineers are commonly supposed 
to be '* rough men/' but after living and asso- 
ciating with them for forty odd years, all over 
the United States, and of all classes, locomo- 
tive, stationary and marine, we have found 
fewer engineers of violent manners and rude 
bearing than we have in other professions. 
Some may feel that civil speech has little to do 
with success. It has everything to do with it, 
for as a rule, even if men are skillful in their 
special line, we will not encounter them if we 
can avoid it when they greet us roughly and 
are surly in their dealings with us. 

Lastly. 
In these United States no man is above his 
calling or beyond it. If he is a man in all that 
the word implies, he is independent of circum- 
stances and of conditions, and is always In 
demand. The trickster perishes by his own 



153 

sword. It does not take long to discover 
wliethei men are honest or the reverse, and 
once the verdict is given either way no one 
can escape the consequences. Not merely 
honest in the sense that he will not take what 
does not belong to him, but an honest man in 
a moral sense. And with this little sermon we 
say farewell. 



2^ ill ^ 

^ rD 0^ 



•'^?^2^i^** 



INDEX. 

PAGE 

Absolute centres 74 

pressure 98 

Atmospheric pressure 98, 108 

Back pressure 31, 103 

Bearings, adjustment of 57 

badly fitted 54 

friction in 54 

heating in 52, 54 

oil grooves in ... - 53 

perfectly adjusted 58 

Blowpipe connection 13 

Boilers, Babcock & Wilcox .... 129, 131, 139 

Belleville 139 

blowing out 6, 8 

braces and stays for 9 

bridge walls 10, 17 

circulation of water in 136 

corrosion in 4, 7, 8, 10 

crown sheet 9 

deposit from feed water 3 

dirty 9 

evaporative efficiency of 124, 127 

examining i 

explosions 11, 122 

fire-tube 122, 128 

firing 148 

fittings for 12 

government inspection 140 

grate bars 15 

grease in 9 



156 Index. 

PAGE 

Boilers, heating surface for . . 126, 131, 143, 145 

leaky tubes in 2 

limestone scale in 4, 8 

locomotive 127, 145 

maintenance of 146 

oil in 9 

perfect combustion in 149 

petroleum oil for cleaning tubes 16 

plain vertical 128 

Purger 5 

rating of 125 

removing dirt from i, 4 

removing scale from 5 

return tubular 10 

Roberts' water-tube 131 

scale in 3, 7 

space required for v^ater-tube 144 

starting a nev^ 115 

tar in tubes of 9, 16 

testing 10 

Thornycroft v^^ater-tube 138 

torpedo-boat . 143 

tubes in 15, 128, 141, 146 

water-tube 122 

water fire-bars 138 

Watson's water-tube 134 

washing out 8 

yacht 128, 143 

Brasses 50, 54 

heating in .... 55 

oil grooves in 53 

solid 53 

wear in 55 

" Chugging " of the crosshead 79 

Cocks, blow-off 12, 14 

gauge 12 

leaky 13 

Combustion 48 

perfect 149 



Index. 157 

PAGE 

Condensers, air leaks in 95 

foot-valves 104 

jet 96 

surface 97 

test for leaky 103 

Connecting rod 'j'j 

to centre 79 

Crank 76 

return, motion 74 

Crank pin 48 

fitting of, brasses 50, 51 

heating of 49, 5 1 

lubricant for 49 

pressure on 49, 51 

Crude petroleum oil, use of 16 

Cut-off valves, setting T^y 

Cylinders, clearance in 19 

reduction of clearance 21 

wear in the 20 

wear on the guides of 20 

Dust-proof ceilings, necessity for 56 

Dynamometer, 34 

Eccentrics 46 

and connections in line 47 

crank centre 68 

of a link motion 71 

rod connections 47 

setting 65, 74 

use for 46 

Exhaust 31 

Feed pipes 11 

Friction diagrams 117 

Gaskets, black lead on 90 

materials for 2 

plumbago on 2 

white lead on 2 

Governors 42 

care of 44 

patented 43 



iS8 Indkx. 



PAGE 

Governors, Pickering '-44 

Indicator cards 31 

Injectors 11 1 

Joints, drawing-paper for • 89 

making 88 

materials for 88 

plumbago for 2 

rust joints 89 

white lead for 2, 3 

Kerosene, use of 24 

Link motion 71 

Lining up an engine 82 

Lubricating 87 

grease for 49 

oil for 55 

Mud drums 11 

corrosion in 11 

explosions in 11 

Nuts, removing Ftubborn 24 

Packing, materials for 91 

Piston 19, 22 

cushioning the ^(y 

leaky 22 

leaky, rings 23 

rings 22 

springs for, rings 22 

steam-tight 90 

Pounding 76 

causes of 77' 79. 81 

Pumps 105 

air leaks in 106 

air pump 95, 98, 105 

centrifugal 112 

circulating 97 

double-acting no 

lift of valves in no 

metal valves for no 

plunger 109 

single-acting no 



Index. 159 



PAGE 

Pump, suction side of a 109 

Radial valve gears 70 

Rivet hole plug 120 

Safety valve 14 

Scale preventers 5, 7 

acid purger 7 

caustic potash 5 

crude petroleum oil 16 

slippery elm bark 7 

Shaft^ main, out of line 79 

Slide valve 24 

action of . . . . .^ 28 

and seat ' 59 

balanced 35 

common connections to 36 

defects in 30, 59 

different kinds 28 

exhaust 6$ 

exhaust lap 59 

exhaust lead 59 

lap 29. 33, 62, 70- 

lead 34, 70 

leaky 26 

metals for, and seat ;^6 

off its scat 25 

plain 35 

ports 27 

pressure on a 34 

stem 25 

stem connections to 36 

stem guides 41 

testing for leaks 26 

use of stem guides 42 

will not work 40 

Smoke preventers 147, 149 

Steam chest 25, 37, 41, 59 

Steam-engine, condensing 93 

Corliss 82 

examination of i 



i6o Index. 



PAGE 

Steam-engine, horizontal 35 

slide-valve throttling 18 

starting a new 116 

v^ill not move . 40 

Stuffing-box 25, 90 

Vacuum 94, 102 

air pump for 95 

Guerick's . 98 

gauge 102 

partial . 96 

Pascal's loi 

perfect 108 

no power in a . . loi 

Torricelli's 98, loi 

working 112 

Water gauge 12 



BOOKS FOR ENGINEERS. 

Steam-Engines and Boilers, An elementary text- 
book for young students. By Prof. J. H. 
Kinealy. Illustrated, 8vo, cloth. 

The Working and Management of Steam Boilers 
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The Corliss Engine and Its Management. By 
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Fireman's Guide on the Care of Boilers. Dahl- 
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Lubricants, Oils and Greases. By I. I. Redwood. 
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Quick and Easy Methods of Calculating with 
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Algebra Self-Taught for the Use of Young Engi- 
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Direct-Acting Pumping Engines. By P. R. Bjor- 
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Sexton's Boiler Maker's Pocketbook. Illustrated, 
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Boiler Maker's and Shipbuilder's Companion. By 
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Management and Working of Steam Boilers, Land 
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Spon's Engineer's Tables. 
Spon's Mechanic's Own Book. The book for 
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Workshop Receipts (in five series). 

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THE PRACTICAL APPLICATION 



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SLIDE VALVE 



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BYQ. LIECKFELD, C.E, 

Translated with permission of the Author by 
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WITH A CHAPTER ON OIL ENGINES 



CONTENTS 

Choosing and installing a gas engine. The con- 
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Introduction. — Lubricants. 

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THEORETICAL AND PRACTICAL 

Ammonia Refrigeration 

A ll^ork of Reference for Engineers and others Employed in the 
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By ILTYD I. REDWOOD 



CONTENTS 

B. T. U. Mechanical Equivalent of a Unit of Heat. 
Specific Heat. Latent Heat. Theory of Refrigeration. 
Freezing, by Compressed Air. Ammonia. Charac- 
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150 pages, 15 illustrations, cloth, $1.00. 



THE SLIDE VALVE 

SIMPLY EXPLAINED 

By W. J. TENNANT, Asso. M.I.M.E. 

REVISED AND MUCH ENLARGED 

By J. H. KINEALY, D.E. 

CONTENTS OF CHAPTERS: 
I. The Simple Slide. 
II. The Eccentric a Crank. Special Model to 
Give Quantitative Results. 

III. Advance of the Eccentric. 

IV. Dead Centre. Order of Cranks. Cushion- 

ing and Lead. 
V. Expansion— Inside and Outside Lap and 
Lead ; Advance Affected Thereby. 
Compression. 
VI. Double-Ported and Piston Valves. 
VII. The Effect of Alterations to Valve and 
Eccentric. 
VIII. Note on Link Motions. 
IX. Note on Ver^^ Early Cut-Off, and rn Revers- 
ing Gears in General. 

88 Pages, 4I Illustrations. 12nio, Cloth, $1.00. 

QUICK AND EASY METHODS 

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Calculating 
With the Slide Rule 

A Simple Explanation of the Theory and 
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